To level efficiently, you should spec into Combat, using Swords. Until you get the Sword Specialization Talent, you can actually use Daggers if you like, the only things that matters being your MH Damage Range (all things being equal, most of the time Swords Damage Range > Daggers Damage Range tho) and your OH DPS (from level 20 speed matters for poison applications - you can just calculate how much +DPS a difference in your OH speed gives you thanks to poisons to chose between comparable weapons.
I highly advise you to spec into combat to get Riposte as fast as possible. It's the most useful skill to level. Some Rogues like to continue into the Combat Tree, some other like to go Assassination up to Relentless Strikes (Remorseless is also nice for grinding), and then come back to Combat Tree, or just go full Assassination until level 40 and then respec for Combat. It's up to you