1. Reduce appearance of dark circles: Draw a triangle with the base under your eye and point toward your cheek. This creates the illusion that your face is lifted and shines light underneath your eye bring the focus upward.
2. Prevent eye shadow from smudging: You can prime your eyelid with concealer if you don’t have eye shadow primer, it works just as well.
3. Hiding acne: Use a green concealer that will cover pimples, then on top of that use a concealer that matches your skin tone and finish it with some powder.
4. Lipstick: Line the outside of your lips with a fine tip brush and a bit of concealer, this will make your lipstick pop and prevent the color from bleeding outside your lips.
5. Contouring: Use concealer to contour your face. Draw a lighter shade of concealer on the areas that naturally catch the light and use the darker shade in the areas that are naturally shaded. Once you blend it all together it will make your face pop.
If you need any help, check out this video that show in detail how to apply concealer, different brands, hacks and to see which one might work best for you: