I have had several role-plays already and I love the one I am in now. In order to keep things fresh I do set some rules.
1) Never add perks to any more than one crafting skill, usually Smithing for Warriors, Alchemy for Rogues and Enchantment for Mages. Otherwise the game just seems to get unbalanced real fast and following this rule has helped tremendously. It also makes more sense that someone can not be an expert in everything.
2) Never do more than 2 or 3 major quest lines. Keeping the character in the factions that they would be naturally good at again just makes a lot more sense and to me makes a more focused and enjoyable game.So far I have played:
Nord Warrior. Sword and Shield. Joined Stormcloaks and did MQ.
Imperial Warrior. Dual Weapons. Joined Empire and Companions.
Khajiit Rogue. Archer. Joined Thieves guild.
Orc Warrior (current). Two-handed. Did all Orc Stronghold quests. May join Blades.
Future:
Breton Mage. Pure mage. Join mages guild and bards college.
Dumner Rogue. Archer/dagger. Join DB and do all Daedric quests.