[Hectic]

Seeing as you've got a tan base a woodland paint job will only need OD, Brown and black.
Krylon is my go to for rattle cans.
easiest method is as follows.
Materials:
Paint.
painters tape
waxed paper
alcohol
news paper or cardboard or a drop sheet
paper towels or rags.
sand paper or scotch bright pads

Steps:
Clean gun with alcohol and rags, get all yer grubby oils and such off. Pay special attn to areas you hold or you cheek weld.
next you can rough up the surface with some fine grit sand paper or emery cloth or scotch bright (this step isn't mandatory with krylon but can improve adhesion)
If you sand re clean.
paint your base coat (tan in most cases, start with the lights color)
Krylon (and most sprays) apply best if "dusted" on keep yer can about 15-20 inches away sweep side to side the entire length of the item pressing the sprayer as you pass over (you will notice the paint will be nice and sparce, almost dusty looking) keep doing this going from every angle until satisfied with coverage. For most items it's best to hang them but you can lay flat and do one side at a time if hanging isn't an option.
While your base is drying stick painters tape to waxed paper. Be sure to over lap the tape, wider tape will work best, you are creating a sheet of tape backed by waxed paper.
Once your sheet is done draw some shapes (or just free hand cut them out) you are aiming for woodland camo shapes, keep in mind your working on a small scale compared to a bdu so keep your shapes a little smaller.
I personally would go with shapes that would fit on an index card or smaller.
Now (once yer base is dry) add some of these shapes to the gun (peel from wax paper and stick on) not too many, this will be your tan that shows so balance it based on environment. Or based on your camo if your just going for a close match. Once satisfied dust your next color in the same method. In this case would be OD. Keep going until you get to your black. Now for the black you will basically be filling in the gaps of places that were left uncovered after the brown was painted and the shapes were stuck on.let it dry and peel off all the paint. You can now leave it or clear coat it (krylon offers a flat/matte clear, it'll make your paint more durable to scratches n such)

If I get a chance I'll make this more point form so it's easier to follow.