Some things that I find help sow the seed of RPing:
1. RP about something. Short conversations your character has are great to try to develop a personality, but as Zakky said, talking to your captain gets old pretty quick. It also doesn't leave much room for others to get involved.
2. Continuing from the first point, make your RPs open to other people. If your RP is just about you slaying mad amounts of godless heathens on a battlefield and there is no way for another player to inject their character, you can't really complain. Try to set something up that freely involves other characters. Duels can be great for this. Heck, even training matches. We had one in GX not too long ago, where a training match was announced. There were RPs from both fighters, spectators, bets were made, etc. It has to be something that more than just one person can get involved in. Some other ideas:
-Perhaps your character wants to throw a swanky party or ball. Invite everyone! Wine, bread, cheese, political conversation, the works!
-Two characters in love? A wedding is a great place for characters to interact.
-Need some scout reports while waiting for a battle? Why not collaborate with a couple other characters to RP a reconnaissance mission?
3. Give your character some personality. Make other characters want to be involved in what you are doing. Don't constantly be the "big fearsome warrior who can fell any enemy and is nigh invincible". Have character flaws, have real personality traits, have interesting faults. This is the point I find most lacking in BattleMaster. Think about characters you have read in books. What appeals to you? Actually try to define your character as a person.
4. Do not control someone elses character. Don't do it. Nothing will alienate a player from RPing with you faster than having their character do things in your RP.
5. Be prepared for opportunity. Sometimes you will fire off an RP and have someone respond immediately. If you find yourself online with someone at the same time, it is a great chance to bounce back and forth shorter RPs that move along quickly, making for an enjoyable read. If you find yourself in this situation, take advantage of it!
These are all my personal observations on Role Playing and what I have found to work and not work. Don't take it as gospel by any means, but I hope it does provide some insight.
