I'm by no means a pro at CS, but I figured that I'd share some of what I know with you. Most people in CS have their favorite weapons and think that all the rest are crap. This just isn't true. As you read make special note of the ones you don't currently use. Start a LAN game with some bots and familiarize yourself with those weapons. Each gun was designed for a different style of play and you need to pick the gun that fits your style. Just remember that the more strategies you know and can use effectively the more unpredictable you will be to your opponents. Each weapon is a tool for a different style so if you want to master each style, you must first learn each weapon.