I think joining competition is not all about winning it.
Of course, winning competition is one of our aim, but besides that, take the experiences that you will get from that competition to make you improve more, get more knowledge, enjoying and inspired by others performance

. So, enjoy the competition.
I think we should play with high concentration, we should really know what we should do, what we are doing when we play the pieces, so, you should be aware about our playing during the whole performance. In the other hand, you should also being prepared mentally. Mental factor is one of the important factors beside playing well. You will play well at that time if you are prepared intelectually and mentally.

And, don't forget of course to pray..

IMO.
If others can explain my points better..help..