I'm going to give some advice for you.
Don't sit in the fleet looking for people to join you for FPs, most people who are in the fleet are there for other reasons, training crafting skills and the like. Not to mention that most of the people there are, most likely, not at the correct lvl for the FP you want to do.
Instead, check who's online on the planet/planets that are the correct lvl for the FP you're looking to do. Why not just spend the few minutes it takes to get to that planet and start asking there instead?
General chat isn't the best way of getting people to join a group, alot of people doesn't like writing in a chat that everyone can see. Instead try to whisper people, and don't just say "LFM DPS Athiss" for example. Instead you could ask "Hi, how are you doing? I'm trying to put together a group for Athiss, would you be intressted in joining?", the worst they can do is say "No", unless they're idiots, in which case you wouldn't want them in your group anyways.