Since your gaming experience will be defined by how much power your phone has, how detailed and bright the display is and how fast it refreshes, and how long you can play without needing to charge, we recommending looking at the chipset/performance figures, the display specs and the battery life length when picking your gaming phone.
You should also figure out if these features are your only priority, or whether you want other areas like cameras, charging speeds or gaming-friendly software features to be good as well.