You're absolutely right, MUDs/MUSHs tend to low-ball players on cash in an effort to slow growth. In my experience running and playing in Shadowrun I've used two different scales:
For high-power games with lots of cyberware, big guns and tons of excitement a normal run nets out around 10,000-20,000 'yen per player, usually leaving the group with enough cash at the end of the game to make one big purchase or several little ones. Most players found this satisfying as they then felt that you could actually get decent gear after chargen.
For more gang-level gritty games where players didn't start off with a lot of cyberware and couldn't buy every gun they wanted we tended to keep things much lower. 3,000-5,000 'yen per player was about right for a good run, but in order to keep the flavor there were also a lot more sessions when the runs didn't pay at all.
So, while it does depend on the tone you want to set, those are some guidelines that worked well for me in practice.
How To Learn To GM
There are a variety of resources nowadays that can help you accomplish this. There are also many existing questions on this site about GMing that will point you to more content than you can ever consume.
Watch
In your question, you mention wanting to see more examples of real play. There's a number of ways to do so.
Actual Play Resources
- Podcasts capture the entire play session. There's video podcasts too like on Twitch. See Where can I find actual play podcasts for RPGs?
- Session Summaries (aka Actual Plays, Story Hours, Campaign Journals) usually are severely abridged, but leave out a lot of the cruft. See Where can I find transcripts of actual game sessions? and Where to find game session reports?
- Blogs. There's a million blogs about how to GM. Start with the RPG Bloggers Network. Go to the blogrolls of blogs you like to find more like them. Focus in on blogs about your chosen game(s) and play style(s).
- Play by post forums. If you want to watch people actually play in text, there's a million of these too. Many dedicated sites, specific forums on RPG.net, ENWorld, Paizo, etc. In fact, RP-by-post is very popular even when not affiliated with a proper RPG/ruleset.
- Sit in. There are plenty of other people running games, some in public places like your friendly local game store (D&D Encounters, Pathfinder Society) and conventions. See below under "Play" though, if you're going to the effort of being there you need to stop being a wallflower and get on in and play.
Some games also have better advice sections than others - see What role-playing games have good gamemaster advice sections?
Play
In the end though just watching is not the most effective approach to learning. Watching games is less useful experience than actually being in one. Have you considered playing in those games before running them to learn from other GMs? It's reasonably easy to find other gaming groups, you don't have to abandon yours to play in another. Where can I find other RPG players?
Go to RPG conventions, find games at gaming stores, play on forums or G+ (see also Finding online RPG players for a play-by-chat RPG Campaign?) - just get more experience. The GM was often called the "judge" in the old days, and in the legal world you need to spend a lot of time being a lawyer before you make a good judge. You need to spend some time playing to become a good GM. If you can't think how the players will proceed in a given situation, you need more play time.
Read
There are many books on GMing - see What is the single most influential book every GM should read?
Also try watching/reading relevant genre media. "I don't get how to put together a story" should get its first-order correction by consuming some of that genre and looking at the stories.
Learn
A lot of the problem you seem to be experiencing is pure storytelling. Try How do I get better at narrating/storytelling as a GM? and As a GM, how can I create and role-play diverse NPCs better? Read up on the specific aspects of GMing you feel you're not good at, there's plenty here. Try questions tagged with the gm-techniques tag. Feel free and ask questions here as well about specific aspects of GMing.
There are also a large, large number of RPG forums out there in the world, for every game and type of gaming. If you don't understand something someone posts, you can easily reply and ask.
Do
aka How I Learned To GM
We didn't have these newfangled Interwebs when I was a kid. I GMed almost before I ever played. I did play in a very informal game of D&D in a car on the way to Scout camp, no dice, PvP, everyone had artifact weapons. But other than that, I started out as a GM. I bought a sci-fi RPG (Star Frontiers) without knowing anything about it (I had bought and played a little TSR chit game, Star Force, and was looking for other fun stuff from the same company). None of my friends were interested in GMing and I was in a small Texas town that didn't have conventions or whatnot - life was less mobile and connected back then. So I just read the game books and then ran games for my friends. And I kept running them, and learned from my mistakes and corrected. I read comics and science fiction avidly, so characters and plots weren't that hard to devise. Beyond that, I just learned the way you learn to do anything through practice, whether it's a sport, writing, a musical instrument... How-to's and YouTube videos are cute jumpstarters nowadays, but "Do, and learn from doing" has yet to be eclipsed in being the primary way to actually become good at something.
Fear of "making a mistake" is the dumbest and most paralyzing instinct you can have in life. In a video game you're going to die a couple times off the bat; in baseball you're going to swing and miss a lot before you hit; in baking you're gonna burn some cookies. But you learn through those mistakes. It's fine to do a little reading up ahead of time but the only way to become good, really, is get your butt in gear and do it.
Best Answer
When I think of noir, I think about the following elements: crime, betrayal, temptation (often sexual), urban settings, pessimism, cynicism, and no-win situations. There's also a host of cinematic techniques that don't translate precisely into non-visual mediums, so I'll leave those aside for now.
Shadowrun has crime and urban settings covered, so that's easy. For pessimism, cynicism, and temptation, I'd look at my NPCs. Almost every one of them should reflect those traits in some way. They don't all have to be pessimistic; in fact, some of them should be defiantly optimistic, but that should be something other NPCs comment on. That'll bring home the point that it's a pessimistic world. And everyone should be capable of being tempted by something. Everyone has to have a price.
Betrayal and no-win situations are trickier, because you don't want to kill the fun of the game and if the PCs are betrayed all the time, they're going to wind up expecting the worst of everyone. This quickly turns into a game of turtle. I'd recommend having a fair number of missions that are the result of betrayal. In other words, the PCs should often be hired by someone who's been betrayed and who needs revenge. They're living in an atmosphere of betrayal rather than being betrayed.
Although it should happen to them once in a while. Don't avoid it all the time, by any means.
Finally, coming back to the visual stuff: play it up in your descriptions. It's raining. It's raining cold, bitter rain. The raindrops are exploding like a child's dreams on the cold, hard pavement. Well, maybe not that last.