How to be more outgoing?

I have generalized anxiety disorder, also depression which can put me in moods that make me antisocial at times and I could seriously use some tips on how to be more outgoing. I'm insecure at times and I feel like that makes it all even worst because I'm scared that people will judge me. I have a few friends here and there in a couple classes and I'm the "smart one" in most of them so people usually just know me because of that. I dont really want to do any sports and I'm already in fbla but even at meetings there I don't really know people and I usually sit alone. I really need ideas on how to boost confidence, talk to peers, etc. I would say I'm fairly attractive but people who know me say I'm very intimidating for some reason. Any ideas?