Getting Psyched For A Game actually isn't as hard as you may think. If you're not excited for the clash between two teams, the battle of each others physical prowess and mental wit, then you're not mentally ready to play-- Don't go out on the field. There is never a game where running out of the tunnel into the sea of Blue and Gold shirts doesn't get me excited. Now, getting into the zone is a slightly different story.
Prior to the game I listen to music in the locker room. Let me start off saying that not many people listen to my music, let alone enjoy it. I prefer genres of music such as Metal and Metalcore. (A couple examples from my favorite bands are "A Romance By The Wings of Icar" by It Dies Today and "My Last Serenade" by Killswitch Engage). I then usually grab all my gear, sit in a corner on a stool, turn the volume of my iPod up to a point where it blocks out all other noise, pause about 10 seconds while listening to it, crank it up a little more, then proceed to get dressed. After getting ready I usually just sit in the corner. As sad as this might sound, sitting in the corner is a very pivotal part of my preparation. It allows me to listen to my music to get into the zone, mentally prepare myself for whats to come, and envision myself performing my blocks and assignments. This ritual usually keeps me going until the first series on the field.
When I walk out on the field at the beginning of a game, only the first few plays do I recognize the fans. I can look a fan in the face and we can share expressions. Fans disappear after those first couple plays then just become another blur around you. From there, I am in the Zone. For an Offensive Lineman being in the zone never leaves you. There is always someone rushing against you. Every play is a battle. Adrenaline is always flowing. Your focus can never drift, otherwise pass protections fall apart and...well, picture a Zack Follett and Erik Ainge encounter... :-/
The biggest thing for us is to not dwell on the previous play, good or bad. Stay focused on situations, the current play, the technique your coaches have taught you, and play your heart out. If you do that, nothing but success will ensue.