Being "in the zone" is pretty much all about your view of the game. If the game is a blowout, it's probably not gonna be there. But if it's the 3rd quarter, the ball's in your hands and you block out everything except what you have to do, you have a way better chance of getting into the flow. I always get pumped up like that when I'm in a good mind state, plus just seeing one shot go down can effect your whole game.

What MaxxHunter said

I know that when im in the zone im not really thinking about anything in particular im just playing and going off of my instincts so what i do is before the game i go out on the court and just do game type situtation stuff one right after the other in rapid progression but i make sure when i start that im not thinking about anything. Im not thinking about elavating when i shoot, i just shoot. I dont think about getting low when i drive i just do it and drive. So before the game starts i would go warm up and make sure that you arent thinking about anything you are just doing it. Hope this helps!

i in the zone by making heroic shots and when i sit down on the bench or get to the other end of the court and when my teamates are congragulating lating me on what i did and when the crowd gets hyped.