Help playing baseball...?

I'm a lefty first baseman on my hs baseball team. Now there are two other first baseman I work with, and I'm looking kinda sucky compared to them. I have trouble fielding the ball at times (it'll pop out of my glove) and I'm getting really bad with my consistency when throwing (at times I'll throw the ball infront or above the catcher). It's really getting to a problem because I'm getting benched way too much. Hitting wise I'm doing fine on, but it's just fielding I need help on.