Many of us fail to apply artificial tanners evenly.
Here are some tips for you.
Allot enough time to apply the tanner and allow it to settle, may be an hour or so.

Use a scrub to get rid of dry skin, beforehand, wherever you plan to apply the self-tanner, for a smoother application.
Don't use too much of faux tan, or it shows. Go light on knees and elbows, and don't miss the top of your feet or back of your hands.
And finally, wash your hands immediately after applying a self-tanner, so that you don't end up having bronzed palms.