Renegade Retard said:
-Are you looking to just be better at the single player game, or playing online?
The Single Player mode is impossible. While I can normally whoop up on Masterful bots, playing a good bit into a Masterful single player ladder has me facing Godlike+2 bots who never
ever miss. It's dumb. And frustrating. That's probably another thing that turned people away and led to the game's low player counts, but that's another topic completely.
Coming from Halo, you're probably jaded into thinking that's how UT is, and that's not the case at all. There's a lot to learn with UT, whereas in Halo basically all you need to know is how to use the rocket launcher and pistol and bunny hop at the right time (haven't played Halo 2 multiplayer, but I'm sure it's same idea). With the crazy moves you can pull off in UT, the rocket launcher does not automatically dominate because it's easy to avoid. Thus, you have to change around your strategy for using it if you want to hit people with it. And that's just one of the things you've got to learn...
Watch some demos of the 1773 players and see what they're doing, then try to mimic it. I've heard it takes a month to become good (on an ownage level) at this game if you've got 1773 FPS skills already, but for the rest of us, it takes quite a bit longer and quite a bit of dedication. I've been playing UT2003/4 for two years now and I still get owned regularly.
So, basically, figure out what you need to work on, then try it over and over and over again until you can do it. Repetition will make you improve. Sorry we can't be more specific than that, but the game is way too deep for us to point out everything you've got to know, and a lot of it just comes from experience.