You need a "gateway" friend who has a good single social life and can invite you out. A meetup group would be good too.

A lot of my friends are colleagues, but I've also joined meetup groups for activities that I enjoy. I also don't mind getting out there by myself and doing thing like going to the movies or hiking alone. I also volunteer and meet people through my community service.

A question for those of you who got divorced. The ex and I had good friends but with young kids etc I did not really focus me and nurturing my own group of guy friends. Now it seems post divorce those relationships that I had are more distant. So what was the best thing you did to meet new people make friends etc ?