A great makeup look begins with good skin, so make sure you're looking after yours. Develop a cleansing regime and stick to it, and if you find you're having trouble with acne, rosacea, or any other skin condition, don't be afraid to visit a doctor or dermatologist for advice. There's no need to suffer in silence.
Then, prep your skin before you begin applying makeup. Ideally, you should moisturize a few minutes before applying makeup. Moisturized skin will hold product better, without dry, flaky patches. If you have oily skin, don't skip this step, just use a light, oil-free moisturizer.
Also, consider a primer. They may seem like an unnecessary extra step, but not only can they target specific skin concerns (like excess oil or redness), but they also create a perfectly smooth base for makeup and help extend staying power. Eye primers have a tint and work like a foundation on the eyes so colors appear brighter and more even, brilliant if you're using a bright or light color.
