Always remove your makeup before going to bed!
Ok, here we go - collective groan. I know it's not the most fun task and when you're ready for bed it's hard to force yourself to go do it but it really is important. I used to go to bed with my makeup on all the time. It seemed like cleansing my skin at night would only aggravate it and I couldn't be bothered when I was already tired and ready to relax. I grew tired of waking up with leftover remnants of mascara around my eyes and a grimy feeling on my face. I had to remove my contacts every night anyways so I figured I'd add one more step to my routine. Then when I got my Clarisonic Mia I really made the effort to remove my makeup every night and deep clean my skin. Now I wash my face every single night and it doesn't seem like such a chore. I go to bed feeling clean and wake up feeling fresh and I've also noticed that my skin looks healthier just from taking that extra step at night. I can't imagine not removing my makeup now.
Going to sleep with your makeup still on can clog your pores and damage your skin. You don't have to use fancy tools or cleansers - just form a habit out of removing your makeup. It only takes a couple of minutes and makes a huge difference (in your mood and appearance!).