The primary function of makeup for women is to accentuate certain features while downplaying "flaws." When it comes to camo face paint, you don't need to worry about the latter—the turkeys really couldn't care less if you have a pimple—but the former is quite important (if in reverse). What you want to do is to take all the things about your face that scream "human" and "predator" and obscure them. For example, when women are putting on makeup, we focus hard on emphasizing our eyes...but when it comes to camo, you want to do the exact opposite. You see, you share those forward-facing peepers with just about every predatory animal on the planet, so prey animals from all the rungs of the food chain recognize them as dangerous.
The other goal of women's makeup is to make the most out of the way light strikes our faces. Look at yourself in a mirror with a light that is either overhead or mostly overhead, as the sun would be if you were outdoors. You'll see that it casts shadows in your eye sockets, under your nose and your cheekbones, while highlighting your forehead, cheekbones, the bridge of the nose and the chin. Again, you're going to want to reverse this effect using color, which will distort the lines of your face and make it less obviously human-looking to a wary animal.
The final goal of women's makeup is to emphasize the symmetry of the face. As with all of the above, the goal of camouflage makeup is to distort that symmetry. Things shouldn't match up from one side of the face to the other.
There are a couple of other things you'll want to keep in mind. First, you'll want to get a general idea of what the terrain you'll be hunting looks like. In winter woods, for example, you should focus on a monochromatic palette consisting of grays, dark browns/blacks and white. In the spring, you'll want to ensure some pale greens are in the mix as well. Secondly, you'll want to keep in mind that very few things in the woods are horizontal, so your camouflage should be largely designed of vertically (or diagonally) oriented patterns of color that won't stand out among trees, reeds or grasses.
Here are some more hints to help you camouflage your face:
1. Start with a makeup primer. Yes, that's a thing, and it works on the same principle as primer for any other kind of paint. It makes application easier and smoother and keeps the pigment in place, even after sweating. (Personally, I favor Covergirl & Olay Simply Ageless Serum Primer, which is relatively inexpensive and available in drugstores, but that's just me.)
2. Don't worry about making it look perfect. A bit of smearing or naked flesh peeking through is fine. What you're going for here is something that doesn't look like a human face.
3. Put dark colors anywhere the light will hit you, such as the cheekbones and brow ridge, and light colors anywhere you naturally have shadows. Remember, you want to avoid symmetry.
4. If you've chosen to use "regular" face makeup instead of paint designed specifically as part of a camo palette, remember that there is very little in the woods that is sparkly or shiny...avoid anything with glitter in it and focus on items labeled "matte."
5. Remember to take it off before you head home for the day or you'll get some very strange looks. Baby wipes work fine, but you may find that the pre-moistened face towelettes in the beauty aisle are more efficient for that specific task.