2 topics here, so there are a couple of thoughts on each:
Concentration:
Even in 20/20 and one day cricket it is vital that you maintain your concentration. Assuming you not some sort of odd ball here are some tips that might help.
1. You cant concentrate all the time, so you need to be able to zone in and out. Between balls relax, as my old coach Kev Sharp used to say "Smell the Flowers"! When the run up starts, zone back in, for spin, start when the bowler gets the ball back - if your not ready pull away, even if you do it 2 times in a row!
2. Get a routine. Watch Alec Stewart or Trott, they have a set of actions they do before each ball. If you make this more constant you'll be more consistent, its called NLP.
3. Practice concentration. If you f##k about at nets and try to smash every ball, or spend all your time working on a shot, or some technical thing, you are missing out practice for the thing that your struggling with most. Practice your routines in the nets.
Getting Out (in stupid ways).
Every batsman that has ever played cricket wants 2 things. To score runs and not to get out, so you are not alone it that regard!
There are 100's of things that I could say but here are a few, sorry if they sound harsh, it's all meant to help ;-).
1. Play the ball and nothing else. Don't care whos sending it down, its just a ball. Don't care it they have taken 100 first class wickets, or if they have just come up form the second team. Its the ball you play nothing else.
1.b. Don't play your self. Its the blowers job to get you out not yours! If you are thinking too much you can't play properly. When you cross the line, stop thinking about everything, no technical thing to work on, not what happen last week, etc, etc. for the first 3-5 over, its just the ball your thinking about (some times this has to change, depending on what's going on in the game, but you get the idea).
2. 50 overs is a long time to bat, so's 40, so's 30, even 20 is quite a long time. Brake your innings up in to 5 over chunks. Dont worry about how many you want to score by the time you out. Think, in the next five overs, I want to still be in and I just want to change the strike over. Next five. I'm feeling in/not in I'll try XYZ. (never try to many things)
3. Know your scoring areas. Left arm spin, right arm fast. I score here, here and here. Know where it is you score, and what shots are your scoring shots. If the ball comes where the 2 can combine your in business, if not, wait for a time when it does. - The longer you bat the easy this gets.
Well just a few tips, hope they help.
Ross