Mice aimed at first-person shooters, for one, tend to feature ratcheting scroll wheels—letting you cycle through your arsenal without selecting the wrong weapon—and on-the-fly resolution switchers. The latter will help you snap-change between the broad tracking you need in a frantic shootout and the tight control for lining up a sniper shot. (Sometimes this feature is dubbed something like "sniper mode," and it may involve a dedicated button for getting granular.)
For a high-end system, we recommend 16GB, so you can have more than one gaming session, your messaging app, several websites, a webcam program, and your video streaming program open simultaneously. A midrange gaming laptop should function fine with 8GB of memory, but be aware that many new laptops are not upgradable. You may be stuck with the amount of memory you order.
Gaming laptops can put a serious dent in your wallet, with some of the fancier models costing upward of $3,000. But who says that the right rig has to cost an arm, a leg and the soul of your firstborn? Fortunately for the fiscally conscious gamer, there are some sub-$1,000 notebooks that can run graphically taxing games like Destiny 2 and Shadow of the Tomb Raider at solid frame rates.