I have found that once you get used to it, sleeping on a hammock is much more comfortable than on the ground. Furthermore, you will never have to worry about a ground tarp, uneven, rocky or wet ground, and can probably eliminate your tent as well as some other gear.
Please note this is a guide for beginners, and does not cover more of the technical aspects of hamocking. If this guide has gotten you interested and you want more information on hammocking I suggest you go to the Hammock Forums, you'll find a ton of completely neurotic and awesome people obsessed with hammocks, with a ton of information on all things hammocks. I'm currently planning revisions for this instructable based on the methods that I learned from HF and now use myself, but for this guide should be adequate.
Step 1: Gather Materials
one foam sleeping pad (yes, those cheap, foam sleeping pads you swore never to use again after you got your inflatable pad)
I will be providing to you:
a basic knowledge of knots
A note on hammocks: buy a good, light hammock. No heavy braided cotton line. I got a lot of use out of my Amazonas Traveler before it tore through (don't let it drag on the ground!). When I bought it I paid around $20 at the local sporting goods store, look around and you should find one similar. There are also many options for making your own hammock, and plenty of commercial options. I recently got an ENO Singlenest, which I like a lot so far.
A note on Carabiners and rope: use only load bearing carabiners, designed for climbing. These carabiners end up supporting much more than your weight depending on how tight you string your hammock. For this same reason, the golden standard for rope in the hammocking community is Dyneema, or Spectra, which are incredibly strong, low stretch materials. I now use 7/16" Dyneema that can hold something around 5000 pounds and is very lightweight. Paracord works, but Dyneema would be preferable. Nylon rope will stretch and poly rope won't.