Mid players are often the ones forgotten about on the field but are the ones who carry the most weight out of anyone. Sure the fronts get the kills and the backs do the talking and the lanes, but that is in a perfect world, and in perfect worlds teamates don't get out.
What exactly is the mid? He is the man who does everyones job all at once, and can become whoever he needs to become. But let's look at it the way we have examined the others:
Before the game: Walk the field with your team, again I stress this a lot. You need to know exactly where your back players are going and where they are shooting, as well as where your front players are going. You need to know every step in the play from the person behind you to the person in front of you.
Off the break: You need to be able to fill in someones spot should a key player go down off the break. So keep your eyes on your fronts, and your ears on the backs. Anytime a teamate get's taken off the break they should notify their team with something "I'm hit" or otherwise, there should be no excuse for your team not knowing their down a player. When that happens it's your time to strike.
When a front goes down: If a front goes down off the break simply take over his job, hit his bunker for him...in all reality most back players who key fronts will stop shooting once they hit their target, which leaves the door wide open for you. If he goes down int he middle of the game it is your job to become the front man and to make up the ground that was lost with his elimination.
When a back goes down: If a back goes down off the break it is your decision to change course and take a back bunker or to continue where yor going...remember, while a key position ont he field is good it's not worth getting 2 eliminations over. Stop at the first bunker you come to and try to make up for the lack of paint that your team missed out on from their loss. If a back goes down in the middle of a game it's again your decision. While I would not recommend running back to a back bunker I have seen it done, and quite successfully. Then again I have seen it fail. If you decide to stay where you are the same rules apply as when playing back, the difference is your now half blind. Communication becomes even more important as you need to work with the other mids or the remaining backs to understand what is going on.
The second line: As a mid player you are also the second attacking line. You need to understnad your front and know when he needs your help and when he wants you to cover him. Listen to your back player as well, he'll let you know what is going on. When I run down the field to bunker a line of guys I will sometimes get 2 or 3, well the next body in that dead box had better be my mid player after he followed me and took out 2 more. Remember, one person running down field to bunker their opponent is suicide, two...well no one does that....right?????
Stupidity eraser: I have heard mids refered to as "stupidity erasers", when the communication is less then perfect between a front and a back that is when the mid has to cover up the mistakes made by either two. A front decides to make a key move while he can't hear his back player telling him to sit his @$$ down...he runs anyway...now it's your job to make sure those people who normally would have a shot at him are lieing in the fetal position waiting for God to strike them dead as opposed to the arsenal of paint your sending at them.
Tunnel vision killer: Mids are also the "Tunnel Vision Killers", let's say a key opponent is laying it thick on your back player, they are trying to pinch him out of his cover. Well usually when this happens the player will do something called "Posting", he'll sit out of his bunker and simply stare at where your back player usually comes out of, in hopes to catch him doing a slow snap shot....many players don't realise that by doing this they tunnel vision and lose sight of what is going on around them....like that mid player who just happened to hear that his backs assialant is "Posting out of the left side of the center 40 taco"...the tunnel very quickly is filled with a bright colored goo....
The best way to play mid is to simply understand the roles of the other members of your team. You are the second and last line of hope for your team. Know what the plans are for botht he people above and below you, and be willing to help easy the pressure to let your teamates do what they have to do.