From reading some of the other threads in this forum, it seems there are a lot of people who have never run a Tabletop RPG before who are looking to try. It also seems there are a lot of experienced GMs out there who are diving into the new system. I thought a thread where people could ask questions and post Tips would be useful.
So. I'm an experienced GM, having run adventures and stories in systems ranging from ADnD, 3rd Ed, 4th Ed, to World of Darkness and Shadowrun. I've run GURPS and LARPS, and homebrew systems and freeform no dice games. I haven't done anything in the last four or five years, due to a lack of a group to do it with, so my knowledge of direct mechanics will be bad, but my general GM tips and tricks are still good.
First tip:
F' The Rules.
Be willing, be able, and be ready to throw out every rule in the book if it will make the story better and the experience better.
This is a tough thing to judge, but in my opinion the most important lesson for a GM to learn. Some players really want hard cruchy rules with everything done in stone. You have to learn to judge that, but if you're gaming with your friends you probably already know who they are. Most average players however just want to have a good time. Put your screen up, roll some dice behind, and be willing to completely ignore that dice roll to do what seems like a more fun answer.
If you learn 2 simple mechanics in any system, you can tell a story: 1) How to hit someone. 2) how to overcome an obstacle. Most of the time these are very similiar actions. If you can do that, you can tell any story, no matter what the situation is. Your players will learn how their powers work. They'll learn how to dodge and track damage. You can pick that up as you go.
And then, if the situation calls for it, remember this tip: F' the Rules. If you roll some dice and its a complete route for the players but it be much cooler if they just barely make it.... well do that. Some games even have it as the '0 Rule' or the 'Rule of Cool' or the 'Golden Rule' - its usually only mentioned in the begining then ignored but it is the most important rule in the game - Make the adventure FUN! ignore rules (in secret) as needed. Change things so that the players are scraping by but SUCCEEDING, if challenged. They fail a little bit but find another way. These players are the heroes (no pun intended for SCRPG) and the action stars. They are the protaginists and the most amazing things ever. They want to feel like they did cool things during this nights session. And throwing out the rules when needed is the most important thing to learn.
As you gain more experience, you'll learn when to throw them out and when not to. Sometimes you'll make mistakes. You also have to be aware that some players really hate this. Thats why there are GM Screens. Thats why most GM rolls happen in secret, so that they can fudge the results as needed to make a better story, while still letting everyone share the illusion that its all up to chance.
More General, less world shattering tips:
1) Provide snacks. Everyone is more happy with food and drink. (Unless all your friends are clumsy and will spill all over the board)
2) Don't be afraid to rip story ideas directly from your favorite movies/books/games. It worked there, and likely the players will get a hoot out of it. ALso, there is nothing new under the sun. (The Tropes website used to be one of my favorite resources for coming up with new adventures)
3) If something doesn't go according to plan, don't try to force the players back onto the road. That just makes them upset.
(I have a story about planning this grand campaign, a trip through this island and a mysterious enemy that seemed to be poisoning the land. The players took a ship to get there. Apparently they were in a mood, and decided to become Pirates. They never made it to the island...)
4) On that note, even if you make detailed plans and the players go off the rails, you can still use that stuff. You'll have to reporpose it, but thats your job.
I'm sure others have more tips. Hopefully they'll add them. If you have questions as a frist time GM (not necessary Mechanical questions) I'll do my best to answer them. If they are Mechanical, maybe someone else can :)