1-Stay focused on upward momentum. Meaning do not hang out on holds for minutes getting pumped, instead have a quick shake out, a good breath and continue upwards.
2-Do not over grip the rock. Meaning relax your fingers and forearms. Beware if you are getting über pumped low down on a route this may have occurred because if over gripping.
3-Use shoulder lock off power. Meaning pull down with your shoulder until you hand is at shoulder height.
4-Keep your core tight. Meaning maintain a connection between your upper body and lower body, you should be able to feel a tightness in your abs.
5-Make use of drop knees to gain extra height to reach higher holds.
If you focus on utilizing these tips both mentally before, during and after climbing a route they will become part of your natural climbing style.