Team Team Team
For me and a lot of people I know, soloing in CoH is like watching paint dry. That all changes in a team setting (even bad ones!), the game really shines and is a lot of fun. Don't sit around waiting for others to invite you, CoH probably has the best Chat / Team UI of any MMO I've ever seen, make use of it and build your own teams.
When you interact with others or are attempting to invite people to a team, don't use leet/texting speak, that turns many people away. For example: "wana tem??" will not get many responses if you're trying to build a team. "Want to join a level 24 mission team in Talos?" will allow you to recruit much much faster.
Use your teaming flags, if you feel like teaming but don't want to form one, put your LFT (White Circle) flag up, that way team leaders will invite you first because your name is at the top of the search list.
Disclaimer: There are indeed a lot of soloists in CoH and while I don't see the fun in it, I'm sure there is some merit to it. I'm just pointing out to a new player that some of the best stuff in CoH lies in teaming for most people.