Your face is a wonder of biological engineering and neuroprocessing in a dermatologically delicate case. With your face, you see and are seen; you express yourself to the fullest. Even if you never wear a speck of makeup as long as you live, you will carry an air of finish and polish if you take care of your face. 5 minutes of grooming in the morning, 7 minutes of grooming in the evening, and some periodic attention to your brows and eyeglasses will bring you a tremendous return on your time and attention investment.
Hair on your face should be there with intent*. With this as your base principle:
Those little stray hairs...you know the ones...pluck or shave them.
If you have a fringe/bangs, make sure it's trimmed.
Wear glasses? Keep the frames and lenses exquisitely clean. Evaluate once a year if it's time to freshen up your look with fresh frames. Inexpensive, stylish glasses are available online now, and I can vouch for their optical quality.
Now that your face is tidy and well framed, here's a day of face care:
Everybody wear sunscreen! Sun damages and ages your skin. I'm sure you know that, but...it takes 1 minute to apply face sunscreen. You deserve that minute.
Skin-hair-and-nails vitamins. If things are unsettled dermatologically, or you want an extra boost, try them.
Remove all makeup meticulously before you sleep at night. A cotton pad and makeup remover from the grocery store or drugstore are fine.
Wash your face with a terry cloth and some face wash (regular bar soap is too harsh).
Moisturize around your eyes at least once a day. At night before bed is good.
When you lie down to sleep, make sure it's on clean pillowcases. Think about this: your face is going to be up against that fabric for the next 8 hours.
"Facial" treatments. Somebody gave me one for a gift once. It consisted of having 5 different products lavishly applied to my face to a soothing New Age soundtrack. I was supposed to relax. I didn't do that very well ("what, more moisturizer?") but I thought a facial was a fine way to try a bunch of products.
Your mouth benefits from some specific grooming.
Apply lip balm/lip moisturizer once in a while.
Check your teeth. Don't like what you see? For two weeks, floss daily and brush with a serious whitening toothpaste (Pearl Drops, Rembrandt) twice daily. Then, check back. Better?
If your gums bleed when you floss, be gentle but continue. Also, eat 1/2 a raw carrot or a raw apple once a day. Both of these are great for your gums.
Now your brain and personality have the communicative sensorium-casing they so richly deserve! Go forth unadorned, or apply all the makeup you desire. The end result should be that when someone looks at you, they see...not the extra bristle, not the chapped lips, not the bit of spinach between your incisors...but you.
* Just a note to say that if you are a bearded lady by choice, I am all for your choice. Linda Medley's graphic novel The Castle Waiting has a great bearded lady plot line.