Do find makeup that matches your skin, even if you have to mix colors.
Do bring your foundation down to your neck. You do not want your face and neck to be different colors.
Do explore different looks, colors, and styles. Change it up, be bold and dramatic with your looks. Your makeup can be different when you're going out for a night on the town versus when you're going to the office.
Do have a healthy diet and drink plenty of water. Perfect makeup starts with great skincare. We can't always have perfect skin due to hormonal changes, etc but we can be healthy to help our skin look the best.
Don't make your eyebrows look unnatural. Eyebrows should fit your face. We all have different faces so everyone's eyebrows should not be the same. What fits for one person may not fit you.
Don't apply makeup to yourself or someone else without cleaning your brushes and tools.
Don't go to sleep with makeup on. Makeup can clog your pores and cause breakouts.
Don't stop trying if your makeup doesn't appear like it was done by a pro. You will get better the more you perfect your skills.