Your attitude to the day you are going to have can play a massive part in the way the day turns out.
I sometimes tell a story to disengaged children about riding a mountain bike down a tricky wooded descent. Its a true story and it goes like this: The descent is narrow and in parts very twisty.
There are roots and big muddy puddles all over it, either side is shouldered by boulders, felled trees and tree trunks. If it is ridden without confidence, and by a rider constantly looking at the obstacles inviting disaster, disaster follows - a collision is unavoidable. However, the same descent is easy and fun if this simple rule is followed: Look where you want to go, not where you don't! It's as simple as that - focus on what you want to happen and the chances of it happening are vastly increased. I know this is true, I have the bruises and cuts to prove it.
A smile and a positive outlook really does work. Put your mind onto the right track and you will get there. If you worry about having a bad day you radiate concern and find lots of negatives.
Of course, knowing a few basic tricks will definitely help too...