1. I keep trying to come up with new builds rather than spending more time practicing with ones I've already made.
Hear that! I would do that in MtG almost every other week- I dont know why, but I don't ever stick to a build.
And I know I lost my first 10 games in a row, and still didn't do very good until I learned some of the more subtle nuances of MW- Like- if the opponent equips a good weapon and starts to rush you- forget about the mana flowers and put on some armor type of thing. I still have to think about interacting with my opponent's strategy, I sometimes get to caught up in trying to "Let my build run its course" and thats not often a good idea.
Keep it up for sure! Have you joined the OCTGN facebook page yet? its good since you can plan matches in advance and then talk about your matches latter. It could be a good tool to learn- I know if I lose a game, I can go on to the FB page, and then ask or talk about what went wrong in my game.
(And I know someone is on there looking for a match right now....
)