Hello Siditfc,
The same way you'd shop for a gaming laptop, is the way you'd shop for a gaming desktop.
The big three specs are most important -
CPU speed, Video Card, Memory
If the laptop is primarily for games, and not as much for portability, you will want to try to find a laptop that doesn't have mobile processor. They are designed to conserve less power and as such, they won't give you as much performance. But non-mobile processors will kill battery life faster.
Get at least 2 gigs of memory and get the fastest available. And then look for a model that has a dedicated graphics card, not shared. Shared graphics memory will leech memory off of your
RAM, which will reduce overall performance.
My advice is, unless you absolutely need a laptop as a portable computer and gaming will take second priority, don't get a laptop for gaming. You will notice pretty quickly how it will become obsolete very fast and you will have very few options to upgrade in the future. Primarily the
CPU and video card...aka the two most important specs for gaming.
You are going to pay way more for a computer that will last half as long in the gaming world.