Less common DMing advice.

[RedMage125]

EvilDMMk3, very nice list. I pretty much abide by most of them, even if i don't think about them. But sometimes, these things bear saying out loud, especially for less experienced DMs who want advice on how to be a "good DM".

I think I would add (probably under a whole new section, like "Rules & Mechanics"):
-Be familiar with the rules. You don't need to be an expert (especially if you have a Rules Lawyer player), but it helps. Sometimes this just means being prepared. If you know that tonight's session could involve underwater combat, re-read those rules before the session.
-That said, don't be afraid to ignore the rules. Remember that it is both a game and a story. When these two things conflict, err on the side of cool. Your players will thank you for it.
-"Random encounters" don't have to actually be random. If you think of a fun monster or encounter that would liven up an otherwise boring trip between point A and point B, then plan it ahead of time, and spring it on them as a "random encounter". Encounters like this will be richer, more detailed, and probably more fun if you spent a few more minutes on them (as opposed to actually rolling randomly ona table and then flipping through the books to run a monster you are not familiar with).
-If you want to make a house rule, ask yourself "will this be more fun for my players, or will they see it as needlessly obstructing?".

It's not your job to manage the group, schedule things, or sort out player conflicts. It's also not your job to make sure everyone has "fun".

It's your job to follow the rules of the game, and to play the world.

It is explicitly your job as GM to make sure the group is having fun. If the rules or the plot are making the game unenjoyable for your players you need to change them- that is why you, specifically, are the GM, not a booklet.

Obviously you can't always do the job perfectly- some players don't fit certain game styles or can't be pleased, and sometimes you're going to make mistakes, but this "I just run the game and tell a story" attitude will ruin your campaigns.

I'm with Feddlefew. It absolutely IS your job to manage the group. Scheduling is everyone's responsibility, as is showing up when you said you would. You should always try to make sure everyone has fun, but that responsibility is to the group as a whole, and not to each individual.

And it's not your job to "follow the rules" (at least, as I perceieve you to be saying), because house rules can be really fun, unique and interesting. Your players should somewhat know the rules of the game you're playing (ideally, anyway), to include any house rules in effect. What you need to do is be a fair and neutral arbiter of whichever rules you are choosing to play with. Don't play favorites among the PCs, and remember what's good for the goose is good for the gander. If you're playing 3.5e, and your players don't want "confirmation rolls" on crits (so they just get the crit if it's a critical threat), then that applies to monsters and NPCs as well.