Destiny

- The first time you do a story mission or a strike (dungeon) you get a HUGE bonus of XP.

- Running it a second time gives you 0 bonus xp, you only get the xp you get from kills. You would get exactly as much XP from doing anything else, including farming. (Doesn't mean you should farm, but you could do patrols or whatever)

- So obviously DO EVERYTHING ONCE. Then when the next story/strike available is too high level, you can just kinda fuck around in PvE or PvP. (Note: your average pvp match lasts ten minutes and rewards 4000 XP each time win or lose, which is only a little less than you get for a "hard" tier bounty, so definitely consider pvp if you can even remotely tolerate it.)

- Level of your enemies doesn't matter for xp! You can kill level 1 mobs with friends co-op and get just as much XP as you do from killing guys on the latest story mission on mars or whatever.

- Problem is; getting to the soft-cap (20) in this game is extremely easy. Everybody is already past 20. So yeah, you're just gonna have to burn up to 20 doing shit mostly solo. You could ask friends to join, and it could be fun, but they won't get much out of it. But 20 also won't take you long at all.

- Once you're 20 (pretty much as soon as you've done everything once) then you have to start collecting gear to level yourself past 20 up to 30. This is called "light level" and it works like ilevel in WoW. Its your equipment level. Heroic dungeon gear will get you up to like 27 especially if you upgrade it with ascendant materials you get from doing dailies, and then you can run the raid to get raid gear and get to 30.