Up to date fractal guides?
farming the short ones (usually 40) repeatedly is very profitable
doing the dailies is very profitable
For mechanics alone, gw2dungeons.net offers all the details, including class-specific suggestions and instability mitigation.
People farm 10 (or better: 40) for the chest loot and the first room of volcanic for mist essence (and random loot) (the level depending on your AR and your team’s comfort with the instability — higher being better).
You can successfully run most fractals with just two people, if that’s all you have — it’s a pretty good way to learn the mechanics well.
John Smith: “you should kill monsters, because killing monsters is awesome.”