The basic goal is very simple. You want to create a smooth canvas with even color upon which you can later apply all the other cosmetics (lipstick, eye shadow, etc.) to finish your look. Getting there is not so simple.
The first thing to remember is that we are discussing "beard cover", not foundation. Beard cover typically goes on underneath foundation, though it can stand alone, and it is usually a shade lighter than the primary foundation color.
The advantages of cosmetic cover sticks are their ready availability, tremendous color options, light consistency and price. They also are usually hypo-allergenic so you shouldn't break out after using them. If you go out a lot you probably should consider one of these. A good choice, if you can find it, is Max Factor Pan Stick. You might also want to work with Physician's Formula foundation, which is quite opaque and usable for beard cover. Pan Stick comes close to theatrical quality products put out by Kryolan and others, but like all drug store cover sticks/concealers it is relatively light. That's great if your beard is thin. Not so good if you have a lot of live follicles on your face. Like other cover sticks it is also tricky to use if you plan on using foundation over it.
Good cover creams are a little harder to come by but the best is probably Johnson Products' Dermablend. This product has been around a good long time, is very reliable and has the opacity to really do the job. It is a definitely good choice for those who have medium to light beards. I tend to favor theatrical cosmetics for major beard covering work because they are the most opaque and can be quite "stiff" in consistency. Because high quality products like KryoIan's DermaColor Camouflage or Face Cream Stick have this "stiffness" they can be applied quite thinly, cover extremely well and will stay in place when foundation is patted on top of it.
Several years ago I would have told you that the big downside to any theatrical product is that they are not intended for daily use. Kryolan's DermaColor Camouflage is the exception.
This product, while used for the stage, has been reformulated for everyday where is commonly used for people who have suffered skin discoloration due to burns or have port wine skin stains.
As good as DermaColor and DermaBlend are, anything as opaque as these are can cause acne if worn a lot. It's pretty simple. Clogged pores are the basic reason people get acne and these product are efficient at that. Be sure clean your face thoroughly before turning in.
When I look at my cosmetics these days I find that my most valuable weapon is the most basic cosmetic of all: powder. Years ago, when I really stunk at doing my face a wonder drag queen from Oakland named Timmi Ryan told me, gently, that the key to a great look was good powdering. Timmi taught me some great tricks that I want to now pass along.
First, clean you face perfectly. If you have a stubborn beard use a hot, damp towel on it first, just like the old barbers did (they knew what they were doing). Shave close with a high quality blade. No electrics! Feel around for stubble and scrape it as close as you can without tearing your face up. Dry thoroughly.
Put your beard cover on and smooth it out beyond where the shadow ends. Use it all over if you can, thinly where there is no hair, but enough to provide an even color. If you don't want to do this then feather it out so that it dissolves as much as possible around the edges.
Now here are the tricks.
When using this brush use the same kind of motion you would use if you were feather dusting. Then comes the key action: use the palms of your hands to Press the powder into the beard cover. You're trying to fuse the powder and beard cover together so that you'll have a stable surface for foundation.
If you use really good powder, like that sold by a company like Prescriptives or Lancome, it may have enough color to do the job you want. The powder becomes your foundation and you put you blusher, eye makeup, etc, over that. Then when you've finished putting the colors on, powder again, only very lightly, just to take the hard edge off.
If powder isn't enough, and it might not be, then you are going to have to put a liquid foundation on. These days, since I'm not using beard cover, I like to put foundation on with my fingers because I can spread it very finely, but when I used the beard cover/powder combo I would not touch that primer with anything except a cosmetic sponge.
Dab a bit of foundation on the sponge and lightly pat on your face, don't rub it on or you'll wreck your primer. You don't have to baby it, just try not to move anything around. When you've finished, powder with the brush again, lightly. Then put your blusher and everything else on. Powder lightly again but with the brush.
Again, if going out a lot in the day is your plan and you want to wear casual outfits you are probably going to need some electrolysis. Hard to get around that.
You don't have to look like Nixon during the debate with JFK. Just imagine what might have been if someone had given him a tube of Dermablend in 1960? Nahh, think about Marilyn Monroe in the White House instead...