What would be considered common sense advice for anyone just starting out? Im in a campaign now and I am wondering what would someone who has expierenced life in the Sixth World? Like just overlooked advice and stuff.

Be paranoid, yet practical. Even greenhorn runners know betrayal is part of the biz, so most runners should be doing almost as much legwork on the Johnson as on the target itself. But don't let your paranoia overwhelm you. Sometimes the door has a grenade set to go off when it opens, but sometimes it's just a door.

Also, your backstory probably helps determine your approach, in character. An ex-ganger street sam is probably all about that sweet, sweet violence, but an ex-corp street sam probably pays more attention to stealth.

Oh, and get a feel for your group. Don't play Black Trenchcoat in a Pink Mohawk game, or vice versa. Try and mesh with the other players as much as possible. If everyone wants to ply an over the top, Kung Fury style game, then great, but everyone's gotta be on board, because a player who wants a gritty, neo-noir game isn't going to have fun when everyone else is flying on jetpacks fighting Zombie Dunkelzahn.

What are Black Trenchcoats and Pink Mohawks?

Black Trenchcoat and Pink Mohawk are different styles of running and playing Shadowrun. I'll copy something from Run Faster that sums it up nicely.

Black Trenchcoat and Pink Mohawk
You might have heard these terms tossed around among
Shadowrunplayers: “Oh, I miss the old Pink Mohawk–style of the
2050s!” or “Her game is a lot of fun but sometimes it gets a little
too Black Trenchcoat for me.” But what do they mean, and what
do they have to do with your game?
Simply put, they’re two different playstyles. In other games
they might be called “cinematic” and “realistic,” or “four-color”
and “grim ‘n’ gritty.” Pink Mohawk-style games emphasize style
over realism, allowing for things like big, bombastic battles where
the lead flies thick in the air and with the right dice rolls runners
can perform actions that might not be technically possible in the
real world (or even the reality of the Shadowrunworld). Characters
tend to be long on style, make a lot of wisecracks during combat,
and take a lot more risks because they know that the heroes
(almost) always survive in the end, even if they don’t win. The
name comes from the art style prevalent in the earliest editions
of the game, where many of the archetypical characters had a
“bigger” but less realistic style than more modern characters.
In the game world, the change could easily be chalked up to
fundamental shifts in society: things were different in 2050 than
they are in 2075, just as they changed from the 1960s to the 2010s.
Black Trenchcoat games focus more on gritty realism. Bullets
and magic are much more deadly, the world is less forgiving of
mistakes, and teams tend to spend a lot more time planning their
runs and carefully infiltrating their targets instead of busting
in with guns blazing. You’re much more likely to see intrigue,
backstabbing, and double-crossing in a Black Trenchcoat game;
player characters are suspicious and bestow their trust rarely,
and even their own teammates might be pursuing agendas that
put them at odds with each other. Black Trenchcoat games might
also get into some of the darker aspects of the world, like torture,
extreme violence, and sexual themes.
So which one is better? There’s no right answer for that.
Shadowrunworks equally well in either style (or some combination
of the two); it’s just a matter of the gamemaster getting together
with the players to figure out which style everybody wants to go
with. Campaigns can run the gamut from a completely unrealistic,
high-cinema world where the PCs take on armies singlehandedly
and come out on top, to settings so dark and grim that everybody
knows to have a spare character on hand for when the existing
one is inevitably killed in some gruesome way. Both can be fun,
and both can be satisfying, as long as everybody agrees on the
boundaries and knows what to expect.

What kind of game you run is up to you, but everyone should be on the same page.

Yup, and while Shadowrun can be simplified to a continuum running from Pink Mohawk to Black Trenchcoat, the truth is that Shadowrun can support a wide variety of playing styles. It can be a game of cold, hard pros. It can be a film noir campaign where the big villains are untouchable and the heroes all have feet of clay. It can be a game of backstabbing petty criminals. It can be a game of idealist, neo-anarchist antiheroes sticking it to the man. So it is a good idea to ask your GM what kind of game he is running, so you can make a character that will fit into that world.

Some very general advice, though:

Shadowrunners are professional criminals hired as deniable assets to do difficult jobs, usually some kind of corporate espionage or sabotage (although they can also get hired for many other kinds of jobs). Contacts, non-player characters that your character knows, are an important part of the game. They can get you the illegal gear that you need to do your job, or even to exist in the shadows (fake IDs, places to lie low until the heat dies down, etc.). They can find out information for you, or provide services such as patching up a wounded comrade or buying that crate of stolen guns you have in the back of your van.

Shadowrunners tend to be specialists (the game mechanics encourage this). You want to be good at something - you have limited resources to build a character, so if you try to do too many things, you will not be very good at any of them. Remember, these are supposed to be professional freelancers. But... don't put so many resources into one thing that it is all you can do. If you are a sharpshooter, fine, but be able to do a few other things, like notice ambushes, move stealthily, drive a car, etc. Finding exactly where the sweet spot is, is something even veteran gamers will disagree on. This is an area to ask your GM about. For example, in some campaigns, social skills might get used a lot, while another GM might rarely call for rolls.

Another thing to ask your GM about is the game's power level. Shadowrun does not have character levels, just dice pools based on Attribute plus skill, with modifiers. Characters built with the same character creation rules can vary widely in power. It is easy to spread yourself too thin by mistake, but it is also easy to get a powerful character simply by making a few logical choices while making that character. Everyone doesn't have to be equally as powerful or focused. If someone wants to play an alcoholic detective who is a bit sneaky, good at finding out things, and a decent shot, while another player is playing a minotaur who used to be a Mafia enforcer, with cybernetic augmentations to make him even more fearsome - well, the first character can do more things, while the second character will be vastly better at combat. But it is a good idea, again, to ask your GM what kind of game he is running. If he is running a film noir game of low-life losers, the minotaur might to a bit too tough for most encounters. If it is a game where the group goes in guns blazing, the detective might feel inadequate plinking with his pistol while everyone else opens up with full autofire, and be frustrated that he never gets to use his other skills.

Thanks for the advice everyone. I really hope my Gunslinger Adept doesnt suck then.

Gunslinger Adepts can be very, very good, so you are off to a good start. My main piece of advice, which piggy backs on what others have said, is simply to watch how the game goes over the first few sessions and see what you, and/or your team, are doing well or not well. This will also help clue you in on the style of game that your GM wants to run. If you see that you (or your party as a whole) are lacking in a particular area and its really hurting the team, then think about boosting a skill in that area if you need to. Just remember that some skills work better as secondary abilities than others. A Gunslinger Adept for instance, probably will not be a great hacker (probably, depending on edition, etc.), but there's no reason why they can't learn to drive the get away van if you keep finding yourselves in chase scenes with nobody in the party able to drive.

Most importantly, have fun!