I'm level 21 and tanked heroic missions plus Hammer Station and Athiss last night with no real difficulties. I am completly speced the the tanking tree.
This is not WoW tanking where I tanked with all 4 classes. Your goals are not the same. Here your #1 priority is to keep the hardest hitting mob on you. Let the DPS handle the adds, and keep everything off your heals. This is contrary to WoW where any mob in a dungeon could drop your DPS before they knew what was going on.
Feel free to request CC and establish kill orders. That's harder to do in pugs especially given a lot of SW fans are new to MMOs.
I like to use my taunt to ping pong the targets the DPS is going after, especially when the mobs are melee and dps ranged. You can also force leap to any mobs that are standing on your healer to get some aggro and stun them.
The usual rules still apply, keep mobs off your heals, dont stand in anything, kill healers, then casters, then melee first and don't break CC.