You know, 13 has always been my favourite number. People have always said it's unlucky. I don't believe them. I think luck is subjective, like pain. If you think something bad is going to happen and you stress over it, you are going have something bad happen. Alternatively, when you think nothing bad can happen, something bad will happen.
Luck is something no one can really control. But I think there are ways to try and augment it. Not will little meaningless charms. With things that actually have real meaning. If you get good luck charms and don't believe in the power they may or may not hold... They are useless. The person puts the power in the charm. You give yourself these chances.
Just remember that you make luck happen. Some magic charm isn't going to make it happen for you.