The D&D 4E DMG has definitly a lot of good advice for beginner Dungeon Masters. It even tells what kind of different styles there are or one can choose, so its not saying there is only 1 way. It even includes advice ffor what to do to prepare depending on how much time you have. Tipps on how other players can take burdens away from you, how to teach new players (since this will happen) the game. Exact guidelines with examples on how to make encounters (with encounter math which works), including non combat encounters (traps, puzzles, skill challenges) and non combat ways to give experience (the encounters + quests). (The skill challenge part was for a lot of people not clear enough, but DMG2 did this better). How to use existing adventures, how to fix problems which occurs, how to build your own adventure.
Of course you still get better with experience etc., but the 4E DMG does give enough advice for someone such that they can start being a GM: