I'm not a DM who forces players to speak in character or come up with backgrounds. But my regular players did all that crap anyway. In the states I played D&D campaigns with a small group of close friends, along with guest players who popped in and out of adventures. Everyone in the core group had known each other for at least several years, so nobody was self-conscious about getting in character.
|Monk: You get to drink...from the fire hose!|
My players ran a variety of characters, but stuck to their roleplaying guns. One, who usually ran a dwarf, was in character so often he usually became the de facto party spokesman whether or not he screwed everyone over. One always ended up with a "heavy" - a supporting character who spoke in threats and grunts - even if he played a wizard or a bard. Another played philosopher. His characters acted as either the moral compass or the devil's advocate when it came to decision-making. Then there was my favorite player: the one who ran a long list of impulsive characters totally cool with going out in a blaze of glory.
The character-heavy party could be intimidating to guest players. Some were girlfriends, relatives or work buddies who had gone their whole lives without seeing a d20, suddenly finding themselves at a table with adults pretending to be dwarves and wizards. I came up with a quick rewards outline to help these newcomers fit into a close-knit, role play-heavy game. It's simple and it's worked pretty well.
1) What does your character want?
Encourage them to choose a goal achievable in one or two sessions. (Gold, sex, gratuitous violence, solution to a puzzle, a piece of information, revenge against something in the dungeon, etc.) When they achieve this, give them a +10% bonus to their total XP or a minor boon/treasure.
2) How do you know the other characters?
Use this. Give a small experience reward when they play off the relationship in an interesting way.
3) Assign a catchphrase.
Something random and offbeat. Not too specific, not too vague. If they can use this catchphrase appropriately in play, give a bonus to their next dice roll.