Weapon Suggestions for Modern Warfare 2?

I'm new to the game and want to know, what do you think of my weapon class and how i can improve it. TAR-21 Laser Sight, G18, Semtex, Flash gernade, Sleight of Hand Pro, Hardline, and Commando Pro. How can i improve my class? remember, I'm only level 23(only got the game friday)