I really have to wonder what people are doing that say they've been playing for more than a year and haven't gotten 1500+ comms. I had over 1k before I lost my Sprout, and that was during late HW.
Some easy ways to get comms, as any role:
1 - Say hello in some fashion at the start of the dungeon. Make a macro if don't feel like typing "hi o/".
2 - Play well. Not decent, not ok. Play your job well. Avoid the AOEs, use your support abilities. Due to how many mediocre players there are, it's not hard to stand out.
3 - Be social and friendly. Talk about upcoming changes to the game you like, how excited you are for getting that item you're close to getting, how excited you are about an item you recently got. I'm pretty non-social in most settings, but I do try to get people talking, especially in Prae.
4 - Wish people well at the end of the dungeon.
5 - Be the Last Man Standing when it comes time to leave the dungeon. Sometimes people will try to comm someone and they'll leave before the comm be made. The window is already open and they'll just click another name. Be the only option and you can get that comm.
Biggest way to get comms that doesn't rely on role, though, is to be friendly and social.
If you're comfortable with playing Tank or Healer, both of those roles are more likely to get comms than DPS ever will be. A Lala will boost that chance even more. A cute/witty name for your Lala will boost it even more. I know Lalas are food, not people, but they still comms more frequently than the other races.