Have a look at Ricky Ponting's batting masterclass on the Sky Player mate. Interesting concepts on his style of batting and train of thought.
This is good advice which I follow.... I don't have a 10 point plan which I write down before going to sleep e.g. I'm going to get a 100 etc but saying 'watch the ball' helps me focus as the bowler is about to release.
I sometimes open for my team and am happy to face the 1st ball so the most important thing for me is to get an idea of what the bowlers are trying to bowl the first few overs and see myself in (nothing extravagant but if there's a ball to hit i.e. to drive along the ground or that's clearly wide of my stumps then I'll go for it as I don't want the bowler to get settled or feel like he's on top) adjusting to the pace of the strip (generally slower and lower than the net we train at).
Played a one-off trophy game on Saturday where I opened and faced and the bowler was very accurate so had to wait for the bad ball. Luckily my fellow opener has the ability to punish average/bad balls for 4s and 6s, which takes the pressure off me as i'm more of a driver/cutter so I see my job as to keep rotating the strike and if 2's/4's come along then even better as this takes the pressure off him to hit big. We were chasing a lowish total in a timed game so had 41 overs to play with which also helped us as we knew we were aiming for 5 runs an over and even with the maidens we knew that an over going for 8+ was going to bring us right back on track or even ahead of the run rate.
If we as openers get close to 50 or more without loss then that's a good start for our batting and even though we had a bit of a middle order collapse we comfortably got the total we needed with 8 overs to spare and a couple of wickets in hand.
Chewing gum helps me when I'm batting as does releasing my focus in between balls where I enjoy the view etc until it's time to focus again. When you're in the middle that's all you should ever think about so keep the negative thoughts out and if you have a close shave with the previous ball then think of 1 word to correct it next time or practice the shot before the next ball.
Hope this helps...