What do you look for in an FC?

[tinythinker]

Tangent, but I do think "try before you buy" is important for that very reason. IMO, in most cases, joining an FC should be pretty "no strings attached" for a month or so; if you give it a couple weeks and decide it's not for you, there should be no bad blood for leaving.

Agreed, but you never know. There's no formal etiquette for such things, nor even an informal established norm for them. Personally I like when FCs (guilds, clans, whatever the name) have a relaxed, brief interview where you can just ask a lot of stuff and as you say have no pressure to stay if it doesn't look like a good fit. It can be a really great FC with wonderful people who are fun and active yet not be a great place for you at that particular time.