The Penny Arcade Guys did a podcast of DnD 4th edition that people seem to have enjoyed, can be found
here.
I think that looking at PbP games is not a great primer for trying to learn tabletop games, because PbP games tend to take out all the table talk, and tend to use character voices much more often. The main part of playing a tabletop game is keeping the game moving, and PbP games don't highlight this social skill as much. That's why I'm pointing you toward the podcasts.
Next, important tip for the DM, you don't 'own' the story. And trying to limit player choices or actions to try to get them back on 'track' typically just irritates the other players. If the players aren't following the story, it's usually much better to take it up with the players, 'above' the game, rather than try to do things in game. So for example, if the PCs totally want to paint their houses instead of trying to rescue the princess, you need to ask the players directly "hey guys, why aren't you trying to rescue the princess, which is the adventure I planned for?", doing in game stuff like causing their houses to burn down, so they can't waste time painting them (or whatever it is they are trying to do instead) tends to just generate resentment among the players.
More concrete example:
The adventure you have planned is the standard princess rescue. Some big bad has kidnapped her, and the King is offering a big reward for her safe return. That's what you expect the PCs to do. Instead the players decide to spend their efforts helping out a minor street urchin character who was introduced last session, and ignore the princess rescue completely. It's very bad to do stuff like kill off the street urchin, or have the street urchin be kidnapped by the big bad too, or have the characters arrested and forced to look for the princess on pain of death, or something.
Next, if the player comes up with a way for their character to be 'awesome' or is just more capable than you thought, and this 'ruins the story' it's usually better to let the results of the awesomeness stand, and save any discussion about rules until after the game gets done. Trying to suddenly negate the characters action in the game almost never goes over well.
Example, you have the party about to get in a fight with a bunch of red court vampires. The party wizard whips out a large zone wide evocation that should flatten all of the vampires. Suddenly making the vampires fireproof, or having a yet another group of vampires show up, or spending several minutes arguing about the evocation rules are usually not good for the game. If you think there was something screwy about that, make a note to check up on the rules after the game, not during the game. The only time that a rules discussion should stop the game are when they might result in PC death or maiming. You can always stamp out new NPCs.
DM of the Rings has some funny examples of ad GMing (and bad players), usually with some reasonable advice under the comic itself.
