Before you apply lip gloss, ensure that your lips are smooth and apply balm. Dust a bit of powder on your lips for longer wear. Then, if you have full lips, apply the lip gloss across the center of your lips. For thin lips, apply the gloss all over. Lip gloss can be applied over lipstick, though how you do it depends on your goals.
Remember that it's best to apply lip gloss over smooth, well-moisturized lips. If your lips are cracked or flaking, address those issues first. Once your lips are in good condition, apply a lip balm. Think of it as paving the way for your lip gloss. It provides a smoother surface and helps protect your moisture. Do this before each application unless you are using a product that is both a moisturizer and a gloss.
You may have noticed that some people seem to need to re-apply their lip gloss quite often. Here's a tip that will set you apart. Put a bit of powder on your lips. It will act somewhat as an adhesive, causing the lip gloss to stick longer.
Then consider what type of lips you have. If you have full lips, you are going to want to apply lip gloss sparingly. Otherwise, it could appear excessive or make your lips look too full. For the best results, apply the product to the center of your lips, smearing across toward the corners. Instead of applying the product near your lip line, smear it up, down, and around with your lips.
If you have thinner lips, you probably want to apply lip gloss in a manner that makes them look fuller. A plumping lip gloss is a good place to start. No matter what type of lip gloss you use, you want to cover your lips fully. What you don't want to do is to apply the product beyond your lip line. If you do, no matter what size lips you have, it will likely appear sloppy and excessive.
In the event you want to apply lip gloss over lipstick, decide what your goals are. If your aim is to preserve the color of your lipstick but to add a bit of sheen, it is a good idea to place three light dabs of gloss on your bottom lip, one on the left, right, and in the middle. Then press your lips together and glide slightly but not fully back and forth.
When you want to use lipstick to tint your lip gloss, the technique is a bit different. In this case, you can apply a light layer of lipstick to your bottom lip. Then use the lip gloss applicator to act somewhat like an eraser and smudge the color over both lips.