Summarize this article in one sentence.
When you wink at someone, you only communicate something if they see you winking. So, before you do anything else, make eye contact with the person you plan to wink at. Try hard not to squint with the eye you are keeping open. The effort of keeping this eye open sometimes results in squinting for the beginning winker. When you first start out, this squinting will be hard to control. Again, with practice, you'll find you are doing this less and less.

Summary:
Make eye contact. Don't squint.