VIP: For the love of god, be patient! If you are playing as the VIP, sit back and let your team do their job. DO NOT charge forward blindly; you will get killed and lose the match. Let your team help you, and wait for them to provide appropriate escorts for you from one area to another.
If you are playing on the terrorist side, the building immediately behind your spawn is VERY handy. From this building you can view nearly all parts of the map, making it an excellent sniping area. There are also windows that look out on the initial spawn area of your enemies... if you can get there fast enough at the beginning of the round with a LAW, it is quite possible to kill nearly their whole team before they even know they are under attack.
If you are playing on the counter-terrorist side, the building I just described is important. Taking control of it can make life a lot easier, but even if you don't want to bother with it, definitely keep an eye on it. Snipers love to hole up in there, so don't turn your back on it for long. If you DO take it, however, there is a beautiful balcony that looks directly down on the enemy spawn. One good LAW or a sneaky sniper can do a lot of damage from up there, especially if the other team has poor Recon.
The VIP can't hold big guns, but he can carry any type of pistol. Buy him a decent gun if you have some extra money, it can mean the difference between life and death in a tight situation.