If you try to do your best there is no failure.

All you can do is to do your best.

Always do your best.

You can only do your best. That's all you can do. And if it isn't good enough, it isn't good enough.

It is not enough to do your best; you must know what to do, and then do your best.

Nerves can be useful, as they sharpen you up, make you determined to try your hardest and do your best.