Talent Overview
One of the interesting features about WoW is that all classes get talents. If you’re familiar with Diablo II and its skill trees then you already have a good understanding of talents. Basically, talents improve your character with either passive or active skills. Some areas deal with increased damage, others with increased chanced to strike or even an added bonus to a skill. You receive a talent point every time you level up, starting from level 10. That gives you 61 talent points at level 70. There are 3 talent trees (Assassination, Combat and Subtlety), which have 9 tiers, each progressively demanding more investment in its tree. An example would be the Vigor talent in the Assassination tree. It requires 30 points to be spent in the Assassination tree before you can select it. Because of this, there is no way to acquire more than 1 tier 7 talent as you would need at least 62 talent points (31 for the first, 31 for the second).
Every rogue trainer has the ability to wipe out your talent selection for a fee. Select this if you wish to re-select all your talents. The cost starts at 1gold, increases to 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45 and finally caps at 50gold. 50 gold might sound like a lot but at level 70 it really isn’t that much, that and the fact that you more than likely will not “respec” your talents a whole bunch of times.
I’ll repeat again, you can’t mess up your character when selecting talents. You can always see a Rogue trainer and restart your talent choices. Feel free to experiment to what best fits your playstyle and worst case, it costs you a few gold to change your mind.

Assassination Tree
This tree deals mainly with increased damage from your rogue skills. It also has a few talents that work with talent points. If you plan on using daggers, this is more than likely the talent tree where you will spend the majority of your points.