One easy thing to do is consider that on average 3 dice = 1 hit.
So a skill of 12 dice = 4 hits on average.
Also a skill of 6 with a stat of 6 is 12 dice. So that is very good. I know others on the board will say that is not enough but it really depends on what your game is like. Since you are the GM you know how tough you will make the enemies.
An "average" person on the street would have a stat of 3 and maybe a skill of 3 so that would be 6 dice.
It is very important to think about the dice pools of the characters when you make up your mission. If your characters have 12 dice, then the enemies should have similar amounts (less for "grunts" and maybe a bit more "bosses"). You want your characters to have a challenge but not get instantly killed. Keep in mind SR combat can be very deadly for those that try to just shoot it out head to head in the open. I'm talking about combat here but the consideration of dice pools is important in all areas: magical threats and wards, matrix hosts, negotiations, etc.
SR rules can be a pain in that sometimes they are difficult to track down in the books. My recommendation is that you agree with your players that you will make reasonable rulings if you don't know the exact rule (and it isn't super important) and move on quickly while playing. Later you can track down the rules to find out for next time. Otherwise you can really get bogged down.
Example (This happened to me the other day):
Your player has Vision Magnification in his cybereye and wants to know how that affects shooting his rfile:
So you look up under cybereyes SR p453 and it says
"Vision magnification: An implanted version of thevision magnification enhancement (p. 444)."So you go to p444 and it says
"This zoom function digitally magnifies vision by up to fifty times, allowing distant targets to be seen clearly. For rules on using vision magnification in ranged combat, see p. 177."So you go to p177 and there is nothing there.. because its really on p178.

So you go to p178 and it says
"Making faraway targets look closer (and bigger) makes it easier to use the old “aim small, miss small” mantra your sniper school instructor whispered in your ear. Image Magnification reduces Range modifiers when used properly. In order to use an image magnification system the attacker needs to use the Take Aim action to gain the benefit of the system. This includes both accessories, such as scopes, as well as cybereye enhancements.Great.. so all that and you still don't know what the rule is.. How much does it "reduce Range modifiers"?
So I just ruled in the moment that it reduced the range category by 1 level..
Later we found the actual rules and it turns out that is actually what it does.
Now I can't find where it was.

But don't let this stuff bog down your game or as a new GM you will spend all your time look stuff up in the books.
However.. there are some good "cheat sheets" that others have made that can really help, especially for magic and decking.