[Jtsummers]

I'd suggest finding social environments where you can engage with people in a common activity. Sports (team, or individual but with common practice sessions), trivia, reading groups, etc. These can give you an opportunity to engage with people more but have a directed focus to it.

You may still dislike the people, but with your interaction focused on a mutually interesting topic you may have better success at dealing with those you dislike, as well as finding those you do like. I'd recommend staying away from highly competitive groups (Magic tournaments and the like), because that level of competitive play is often detrimental to other social interaction with the people. Good adult rec leagues are competitive enough to be fun, but most people know they're not pros so they still take a more relaxed attitude.

When you do start finding people you like spending time with, take the lead on initiating social engagements. Especially if they're not all from the same social circles. Invite several people that you like more out to dinner and a movie, or a Friday night at the bar, or a game night potluck. You may still feel a bit of an outsider, but it'll increase your opportunities for communicating and engaging with people and gives you control over the situation (which can make it more tolerable if you're an extreme introvert).