Paint made from chalk, lime and other minerals is a century old technique that has found a rebirth in the last 20 years. With good reason. Chalk paint has beautiful velvety finish, great adhesion and coverage, and sands easily for the popular chippy, aged finish. The wonderful thing about chalk paint is there is no need to prime, striip underlying finishes or insane sanding required. This paint will adhere to any clean, oil free surface.
They are available commercially but can be pricey and come in a limited variety of colors. Here is how to make your own smooth version, cheaply, easily and in any color you can imagine.

Materials

7.5 oz sample pot of FLAT Latex paint (Do not use gloss paint, it will not give the optimal results. Satin or eggshell will work in a pinch, but flat gives the best results)
Heaping 1/4 cup of calcium carbonate, also called chalk or whiting. (For more acurate measurements, it is a 1/4 cup + a tablespoon)
If you live near a ceramic supply store, you can buy it very cheaply and in bulk quantities.
Water
Clean empty paint can or jar with a tight lid.
Clean empty jar for preparing chalk

Step 1: Preparing the Chalk Is Key

The key to a smooth finish with chalk paint is to get your chalk clump free. There is nothing worse than distressing a piece and to hit an unmixed clump of chalk, leaving a dusty void in your finish. To completely eliminate this problem you need to thoroughly dissolve the chalk, yet not add too much water,which makes the paint too thin and runny, ruining the beautiful thick creamy texture we are after. The process is simple. I also use this method to make clump free gesso. You can find that Instructable here.

Start by transferring your 7.5 oz sample pot of paint to a clean empty paint can or jar with a tight fitting lid. I usually just turn it upside down over the container and let it drain, while I carry on with the next step.

Put a heaping 1/4 cup of chalk (no need to sift it, our process is going to take care of that) into a second (clear glass) jar.

Next, gently pour in enough clean water to cover the chalk by at least an inch. Then leave it alone for at least an hour. Allow the chalk to completely settle, leaving the water on top almost clear. The longer you wait, the better the separation. I usually set mine up at night before bed and it is ready by morning.

When the water is clear and the chalk has settled CAREFULLY pour out the water, taking care to disturb the chalk as little as possible.

Now let it settle AGAIN and pour off the water a second time. You can repeat this step as many times as you feel necessary.

***WARNING Don't pour the chalk water down your drain, it can cause clogs. It can actually be poured outside as it is a naturally occuring mineral.

You want to get out as much water as possible, leaving just damp chalk.

Step 2: Mixing the Ingredients

Once you are satisfied that you have removed as much water as possible,
you simply add to your paint and mix well. This method will lighten your paint color a bit so you might want to choose a deeper shade than you want to finish with. ***Helpful hint Make friends with the paint guy or lady at your local store. I have had them add an extra squirt or 2 of pigment for me to compensate. Homemade cookies work. Every.Single. Time. :)

If you feel that your paint is too thin, simply leave the top off of your can and check every hour or so until it reaches your desired consistancy. Resist the temptation to add dry chalk to the mix. That's how you get clumpy paint. It is always best to take your time on the decanting step to acheive the right consistency.

Step 3: Using Your Paint

Chalk paint is a very forgiving medium and will adhere to just about any
surface, including glass. When painted in layers, it allows for sanding and distressing to reveal layers of color underneath for that wonderful aged look. Painting over existing stain can also give a unique aged look. It can be sealed with any conventional sealer like polyurathane, enamel or shellac. I like to use wax, both clear and tinted, as it gives the mellow glow of aged paint and really brings out the colors. This method is so easy and inexpensive, you can experiment for pennies. Have fun and paint ALL the things!