Close-set eyes are basically eyes that very close to the nose line. Makeup tips for close-set eyes are different and the idea is to make them look away from each other for a different look. Here are a few tricks that will help you.
While doing your eye makeup make sure it is darker on the outer corners and lighter on the inner corners so that the eye shape looks extended towards the edge. It is the simple logic of contouring where you highlight the areas you want to and create a hollow where you don't want to.
Play with your eyebrows, widen the arch of your eyebrows. You can do this by changing the way you thread your eyebrows or create an illusion with your eyebrow pencil. Make sure the arch of your eyebrow is at the edge of your iris. This will take away focus from the inner corners.
With the eyeshadows, you must blend it well until they are seamless as in there shouldn't be an end line to your eyeshadow. Blend outwards till the ends don't stand prominent. This trick will help your eyes look widened too. Apply this trick in combination with the first trick.
With the eyeliner apply it both on your top and lower eyelids but make sure it thicker in the end and very thin in the beginning of your eyes. You should opt for winged or cat eye as it takes away attention from the inner corner of your eyes and gives it to the outer corner of your eye.
Another trick with the eyebrows that is very helpful is, extend your eyebrows using an eyebrow pencil or gel. This will give an illusion of wider eyes.