Hey !!!
I am new to Halo and also new at the xbox, i only played FPS on PC CS,UT,Quake. I really fall in love with Halo and i want to be better,its hard times when you have nobody to train. Now i am searching for people who want to train with me in custom games, little maps no time limit and just practice aiming.
I also would look for a Clan with some players who just kill the -Yoink- out of each other in custom maps, i think thats the best way to learn it,instant spawns and just keep learning and learning 
Would be nice to hear from you !