In many ways my first year DMing was a comedy of errors - I took up the reins because our first DM sucked, and I was the only one interested in running the game. To make matters more confusing I was one of the youngest members of the group. (I kind of miss being the young guy at the table.)
I had the DM PC problem for a short while, then realized what I was doing and smashed him with a 16 ton block of stone.
I had the Storyline is God problem for a longer time, where the events were bigger than the characters, as they were dragged will ye, nil ye from event to event. I generally managed to give the players the illusion that they were affecting events, but they really didn't. To this day I have to fight a tendency in this direction. I think that it stems from the same reason that I cannot run a game that I am happy with on the fly. So I now compromise - things that the PCs cannot affect do happen, but if there is a means for the PCs to interfere then they have free rein.
I had the pun filled 'funny' dungeon that even I lost interest in after the second session.
I had the 'Litererary Allusion' dungeon where everything tied in with a work of literature. (I would not run it now, but I still have fond memories of this one.)
Several hack 'n' slash adventures that I only vaguelly recall.
For a while I just
had to use every critter in the game (there was not even a Monster Manual back then). Then I swung the other way and cut many of the humanoid races out of my game - there were no Lizardmen, no Kobolds, no fish-men (I think that the Sahuigin were already around...), trying to make a more 'sensible' setting. (I have cut the races even further since those days, preferring multiple cultures to multiple races.)
Then after about nine months of fumbling I got the swing of things. I decided that my campaign needed a theme, and since I was going to a Catholic school, and we were covering the Crusades in one class and American history in another I decided that conflicts of religion and the subjugation of native inhabitants was as good a way to go as any. The themes of war, religion, and racial conflict have been a part of my games ever since. It was also the first time that I had orcs as the oppressed aboriginals rather than the invading monsters. (Though as far as the settlers were concerned that is what they were...) I have run that world, or variants thereon for a long time.
(My current homebrew is essentially that same world rewritten to fit the early to mid 1600s.) I also cut way back on dungeons and started having social interactions with the NPCs as the center of the game.
I guess that I did an okay job after a while, I ran into one of my old players a few years back, and he had a better memory of the campaign than I did. Father John Semineau (I always spell his name differently every time I attempt it - I am not sure that I ever learned how to spell it properly...) remembered it fondly, though he no longer games, I was surprised at how long I have been using some of those themes in my games (back in 1976-'77 if I recall properly.)
The Auld Grump