In reply to Alex Newton:
Improving technique is a lot about practising technique. How often do you actually think about how you are climbing, rather than just trying to get to the top?
You acquire more techniques by climbing more, but you learn and perfect techniques by practising them repeatedly. Practice good technique every time you climb as part of your warm up on climbs that are easy for you.
How to learn good technique? I can recommend a few resources that will help you, that I wish I'd come across when I first started climbing.
(1) The Self-coached Climber - for me this is still the gold standard on how to learn good climbing techniques;
(2) Neil Gresham's Masterclass DVD Vol 1: illustrates the use of many of the techniques described in the SCC;
(3) 9 out of 10 climbers make the same mistakes by Dave McLeod: words of wisdom from a master climber that overlay the above more specific tools.