iso: IDK, GMing tips?

So, it turns out that I will be GMing (for the first time zomg) a new Shadowrun campaign while our current GM takes a break from trying to kill us horribly.

I have never GMed before. And I'm not actually sure how to do it. So, any advice would be awesome. :D?

aaaaaaaaaagh things that force me to make decisions aaaaaaaagh