This is more of a "tips" thing instead of a tutorial thing.
For your face, it depends mostly on the skin tone of the character that you're going to be cosplaying as. If they have a skin tone that is darker than yours, go for a shade of foundation that is one or two shades darker than your normal colour. If you're playing a character that is lighter toned than you are, go for a lighter shade. If the character is pale - don't go for white foundation, just stick to a tone that is one or two shades lighter than your natural tone and just apply more than you normally would.
And unless you were born with absolutely perfect skin, you are going to have some imperfections - be it redness, scarring or blemishes. When cosplaying, you're going to want medium to full coverage foundation stuff that is long lasting, especially. I'll list some favourite drug store brands so you don't have to break the bank more than you already do.
Revlon: Colorstay - My absolute favourite. I swear by this stuff. It comes in two formulas - for normal/dry skin types and oily to combination skin types. Go for whichever one is your skin type. They make a LOT of colours available for this. There is a downside in that this stuff dries SUPER fast when applying it, so go with your hands and layer it, or take a wet cosmetic sponge and apply it with that.
Revlon: Colorstay Active - This is a light to medium coverage foundation, but it's great if you know it's going to be hot and you're going to sweat. This foundation is water proof, so don't worry about it streaking.
L'oreal True Match - Medium coverage. SO MANY COLOURS, you're bound to find one that matches your skin tone. Not recommended for oily skin types.
Rimmel Lasting Finish Wide variety of skin types can work with this foundation. Rimmel, however, isn't known for their colour variety. Medium to full coverage.
L'oreal Bare Naturale - This is a mineral make up, so if you're worried about your make up looking cakey, or if you're wanting a more natural look to your cosplay, go with this one. It is full coverage foundation with a large colour section. Just be sure to use a different brush than the one that comes with it.
24/7 Mineral Foundation Another mineral foundation. Gives full coverage. Not great for dry skin, though.
Maybelline Coverstick I usually get this one in green. Green concealer is great for covering up redness. This stuff works like a charm. I recommend all of their concealer products.
L'oreal True Match to go with the foundation, but it works for any other foundation you can blend it with.
Revlon Colorstay Concealer Of course!
Almay Eye base + concealer I mostly use this as eyeshadow primer, but it can double up as concealer.
Finding powders to go with these can be difficult, so your best bet is to get a translucent face powder. But, if your foundation brand of choice comes with a matching powder, go with it.
Coty Airspun Loose Face powder A good translucent face powder. PERFECT for setting your liquid or cream foundation. You'll need to purchase a separate puff, though, as this brand does not come with one.
Unless your character calls for it, you won't really need to do anything with your eyes (aside from contacts, if you desire). However, some characters do need a bit of eye make up. Try to follow the pattern of your character. If they wear eye make up, do what you can to mimic it. I'll list a few eyeshadow palettes I recommend, along with mascara and eyeliners
120 Palette: Available via ebay for any where between 14.00 and 20.00, you get a LOT of colours for your money. The shadows are VERY pigmented. Most are matte, but some are satiny or shimmery. Note that a few of the pots will come with the product cracked, due to shipping, but most are salvageable. A little of this stuff goes a LONG WAY. Definitely worth the investment. Just search 120 palette on Ebay.
CoastalScents 88 palette Vibrant colours, wide selection - this is a good partner for the 120 eye palette. You can order this at coastalscents.com - feel free to purchase the warm palette, shimmer and metal mania palettes, all are very much worth the price.
Wet n Wild MegaEyes Creme Eyeliner Good product for little price - this stuff can compare easily to L'oreal's HIP collection. Colour selection is limited to plum and black - the brush is poor quality for eyelining as it's too stiff. Try to find a thinner eyeliner brush instead, and use this brush for your brows.
Wet n Wild Twin liner pencils Perfect for your waterline. Colour selection is limited to black, however, so if you're looking for more colours, you'll want to look elsewhere.
Rimmel Sexy Curves The brush on this mascara is interesting. Helps hold a curl to your lashes. Very buildable and doesn't leave your lashes feeling clumpy.
L'oreal Voluminous THE Drugstore Mascara! The brush is perfect for coating all of your lashes evenly. Makes lashes fuller, thicker and more voluminous with just a single layer. You don't need anymore than that, or you risk clumping. Isn't great for making your lashes appear longer, however, and it doesn't hold a curl that well. But, I love this stuff as I have long, curly lashes by nature. Comes in a normal and waterproof formula.
Maybelline XXL The entire XXL line is great for your eyelash needs. Typically boosts volume and curl, or length, depending on the formula you get. Each XXL tube comes with a side of eyelash primer, and then the mascara.
I'm not going to bother with lipsticks, AFAIK, most cosplayers won't need lipstick.
In terms of wearing make up, you are going to need to prep your face first.
The night before, or the morning of your session, be sure to scrub your face with a nice exfoliating scrub. Several brands make them, or if you want to make your own, go with a mixture of 2 tablespoons of olive oil (don't let the oil scare you - the molecules are too big to clog your pores) 2 tablespoons of honey and 1/2 cup of sugar. Mix and voila, instant face scrub for pennies!
First, wash your face with your favourite face wash. Then, scrub your face well, working down from your forehead to your chin, scrubbing in circular motions for one minute, before rinsing your face. Pat your skin dry and reach for your favourite brand of face toner. (I like Garnier Nutrisioniste Skin Renew) Toner helps keep your face hydrated without activating your oil glands. It works in tandem with your moisturiser - which you may not even need. After applying your toner, apply some moisturiser - any brand you like. Let your moisturiser soak into your skin for ten minutes before applying your make up.
Once your moisturiser has set in, it's time to put on your make up. Put in your contacts before you wear your make up. If you're going with a creme or liquid foundation, apply your foundation first - the method doesn't matter (hands, with a foundation brush or a cosmetic sponge) then apply your concealer. Cover up any imperfections, like under eye circles, redness, scarring and blemishes. Blend it into your foundation. Then powder your face to set the concealer and foundation.
If you're working with mineral foundation, use your concealer first - applying it as you would with liquid foundation, blending it into the skin. Then, apply your mineral foundation and finishing powder.
If you're going to do your eyes, take care of the eyeshadow first. If you insist on wearing eyeshadow, even when your character doesn't need it, stay with neutral tones. Try to make your eyeshadow look natural. Follow up with eyeliner and mascara.
DO NOT PUT GEL OR LIQUID LINER ON THE WATER LINE.
Unless your brand says it's okay for the product to go on the water line - don't risk it. Gel and liquid liners have chemicals in them that kohl liners don't. It's better to use a kohl pencil on your water line.
That should be everything. If anyone has any questions, leave a comment - I'll do what I can to answer :>