By being alone, not drunk, relaxed, and approachable, I get bumped up on her sex wish list. --RooshVThose are some great words from Roosh - author of Bang! (get it now if you don't already have the ebook) - and it's something I've always also been in agreement with.
Honestly, I've never been a good wingman. I've been out and about with good wingmen, but due to my extensive traveling, it's hard to meet new guys that share your level of skill and understand rules of being a good wingman. So, solo is my way to go -- that being said, don't hesitate to go out and have fun with a group of friends (male and female) - just do your approaches solo. This way, the woman has likely already noticed you laughing and having a good time with your friends.
Now, having a mentor or coach with you is a different thing, so don't get confused there!