Okay, so I sold the car. But the Big Red Van works too!
The front windshield area is perfect for placing trays of herbs for drying. If you have a car, rather than a van, you can use the rear window area too. A few sunny days and most herbs are dry and ready to use or store for the dark of winter. Rainy days? Even rainy overcast days get some solar effect. If it gets above 15C for a few days, things dry faster in the car than on my kitchen windowsill. The trapped heated air inside the car is ideal for drying herbs ( not so good for sun dried tomatoes, but that story may have to wait for the next "Fail" Contest)
I've driven around with my front dashboard covered in end to end trays, but you might want to check local enforcement on this. If I'm trying to look 'normal', I put the trays on the floor between the front seats while driving. No vehicle? No problem! See step 4 for other drying methods.
I use a lot of herbs for tea. ( see my "what's in your teacup?" instructable). In the last few years I've been trying to grow more of the herbs I use in my tea in my backyard. It takes a lot of fresh herb to make a small amount of dried herb. (I've read stuff that says to use 1/4 of dried herb compared to fresh)
I don't like the hanging bunches of herbs method for a few reasons. When I've done it the herbs often lose colour and some of them don't dry well where the stems are bunched together. Over the last few years I've improved and streamlined this process, now if I could get the herbs grow bigger, faster or maybe multiply . . .

Step 1: Herb Prep

For this instructable, we'll be processing nettles, but the preparation, drying and storage is similar for all kinds of herbs. If you're wondering why I use nettles see step 2  
I've read lots of herbal posts here and elsewhere that tell you to "cut your herbs in late morning when the dew has dried", although that advice has a lovely pastoral tone to it, it won't work with my garden. If I don't double or triple wash the herbs from my garden, I'll end up with grit in my tea, yuck!  So you cut the herbs whatever time of day you can find the time.
I usually harvest herbs like nettles, lemon balm and lavender at least twice during the growing season. The first harvest of nettles can be taken mid May, when the plants are about 2'/ or 60cm tall. For the first harvest, I'll cut about 4-8"/10-20cm off the top of each stem. This first cutting usually encourages a branching, or 2 stems, from the place where it was cut. This results in a bushier plant, works well with lots of my herbs ( rosemary, basil, bergamot, even thyme). If your nettle plants are nice and tall in mid july, you can cut off the top 1/3 of the plant for drying now, making a final harvest once the seeds are mature, in early fall. ( I don't use the seeds in tea, I have tried to get them to grow elsewhere in my yard, alas, no luck with that so far)
While harvesting nettles, I use kitchen tongs and kitchen shears, if you want to go all out you could put on garden or dishwashing gloves. I usually make a mental note of where the closest plantain is as that will help quell those stings that happen if you let your attention stray during nettle processing. There are lots of plants that can come to your rescue. Dock leaves are probably the ones I've seen mentioned the most, but I don't have any in my yard, plantain leaf does fine. While researching this instructable I saw that rosemary, mint and sage should work too. To use these plant remedies, dock leaf is rubbed directly on the skin. Plaintain leaf gets rolled up between your palms to lightly crush leaf surface, then rubbed on sting. (I'd use the same method with rosemary, mint or sage)
Harvesting!
Using tongs to grasp the stem, cut the top off the plant with the shears, and using the tongs, drop it into your salad spinner.
Nettle leaves contain alkaloids, which in large quatities can cause health issues. These alkaloids are inactivated by drying or cooking. NOTE: if you're putting these in your raw smoothie, only use the top 4 leaves from each plant!
If you're drying these for tea or planning on cooking before ingesting, you can use the top half of the plant.
The sting of the nettle is also inactivated by drying or cooking.

 Once you've cut your plants, place a comfortable amount in your salad spinner ( mine was a goodwill find), fill the spinner with slightly lukewarm water. Agitate the herbs gently with a spoon a few times over the 15-20 min soaking time. Lift the basket out of the salad spinner ( wet herbs in basket, water still in bowl of salad spinner). Look at the water in the bowl, if you don't see any dirt in the water, you're done. If the water looks dirty, repeat wash cycle until the water looks clear. I know this uses a lot of water, that's why you have your watering cans just outside the kitchen door so you can fill them with the used rinse water. Spin clean herbs in salad spinner Now this is where quality control comes in. Nettles are delicious to our insect friends, they also are a popular location for insects to lay eggs on, so you'll want to inspect each leaf, especially the underside for any eggs.  The eggs look like tiny raised dots, often white-yellow). Put any "eggy" leaves aside to go in the compost or throw into the stir fry/soup/pasta tonight. (I have salvaged bergamot leaves that had some powdery mildew, just kept them separate from the good leaves during washing and drying, labeling the mildew damaged leaves to be used first. I don't think I suffered any ill effects.)This is also where you remove any stray plant matter, grass etc from the herbs you are preparing

Step 2: Why Nettles?

Wait a minute! Why befriend a plant that stings like a dozen red ants?  Can't handle it without extreme discomfort, why even try collecting, much less ingesting it?  read on, my friend . . .

Nettles have lots of useful properties, they act as an antihistamine, anti inflammatory, as well as having nutrative effects (contains protein, calcium, phosphorus, iron, magnesium, beta-carotene, vitamins A,C, D, and B complex * from https://www.anniesremedy.com/urtica-dioica-stinging-nettle.php)

Nettles, like other herbs, are medicines. If you have any medical conditions, take any medications (OTC or prescription) or are pregnant or breastfeeding; CONSULT WITH YOUR MEDICAL PRACTITIONER BEFORE USE. Nettles may lower blood sugar, lower blood pressure, act as a diuretic or interact with medications you take.
http://www.umm.edu/health/medical/altmed/herb/stinging-nettle
http://www.webmd.com/vitamins-supplements/ingredientmono-664-STINGING%20NETTLE.aspx?activeIngredientId=664&activeIngredientName=STINGING%20NETTLE

Ok, back to our project

Step 3: Drying Racks

Over the last few years I've done a fair bit of experimenting with drying herbs, the following method works well for me.
You'll need: 
cookie sheets, roasting pans  ( I often put 2 layers of herbs in the roasting pans, each layer on a mesh or wire rack)
I also like using the fiberglass mesh that you can use on the grill or in the oven, can substitute wire racks ( the leaves dry better if they aren't lain directly on the metal pan) 
Cheese cloth or light coloured tulle ( the stuff you'd use to make a tutu out of) Tulle's more durable than cheese cloth and I find it's easier to work with (the dried herbs doesn't get tangled in the tulle as much as it does in cheese cloth) 
Clothes pins or plant clips 
Sun, or car parked in sun 
Place the fiberglass mesh, wire rack or pierced metal pan on top of your roasting pan or cookie sheet. I like the dark metal pans best, but what ever you have, it'll do.  Using the tongs, lay the nettle leaves out on the mesh or rack. Overlapping leaves won't dry as well or quickly as a single layer. You want to avoid mildew/ mold forming on your leaves. I save the stems of most herbs as they're just going to go into tea. When drying, I put the stems under the wire racks ( in the bottom of the pan).
2 days of intemittent sun at 12-15 Celcius, inside of your front windshield, will usually dry a pan of leaves. I cover the pan of leaves with the tulle to avoid the sun bleaching out the leaves and it also holds the leaves in place while carrying them to and from the car. I use the clothes pins/plant clips to secure the ends of the tulle to prevent spillage.
A note on wrapping the tulle: Tulle is quite wide, the stuff I have is about 180 cm/70"wide. I cut mine into 60-70 cm/24-28"lengths, keeping the full width. I put a triple layer of tulle on top of the leaves, then wrap it completely around the pan ( under the pan, then back over the top, so 3 and a half layers on top, one underneath)
  Once your nettles are completely dry, ( should crumble when rubbed between your palms), place in airtight container until ready for use. A zip lock bag works well, press out as much air as you can before sealing. Store out of direct sunlight and away from heat sources. Don't forget to label!

Step 4: Other Drying Methods

No vehicle! Too cold? Just a handful of herbs?
You could put a tray of herbs on a sunny windowsill ( none of my windowsills are all that sunny, so I rarely do this)
Paper bag method- this is what I resort to in the end of autumn when it's too cool to dry things effectively in the car. Clean herbs are placed in a large brown paper bag. ( not more than what will comfortably fit in the salad spinner). I usually fold the top over and staple or clip it closed, I secure it because I've kicked over a bag of drying herbs more than once, scattering half dry stuff everywhere. I don't need that small heartbreak.
Keep the bag where you'll remember to shake it at least twice a day. Shaking ithe bag keeps the leaves from clumping too much, allowing them to dry fairly well without getting mouldy. Resist putting the bags on or next to radiators. I think that diminishes the quality of the herb ( less tasty/flavourful)
Onion/mesh bag- this is my go to method when I've only got a handful of herbs to dry, it also works great for drying (and short term storage) of citrus peels. Shower curtain rings are great for clipping the bag o' herbs to your curtain rods. If the half dried herb starts to look clumpy, stir it around with your finger so it will dry all the way through. If you have a small amount of a herb with tiny leaves, petals or seeds, loosely wrap in a single ply of facial tissue before inserting in the mesh bag
I save all those little "silica gel pack- do not eat" things that come in vitamins and supplements. If I think a herb is only 99.4% dried, I'll add one or two of these in the ziplock or other container when I put them away for storage. To reuse just place the gel packs on a warm radiator or sunny windowsill to "recharge" for the next time
If you won't be using your herbs for a few months, don't crumble them up until you're going to use them. This helps retain the volatile oils.
If you have any questions, ask!
if you liked this, vote!