Luck is needed but it comes at last level. I mean you need to go through the theory first. You must know each and every term used in forex trading like swap, lot size, scalping etc. Then find a good experienced trader and get some tips from him and apply those tips in your demo account. Try different strategies and the one you feel comfortable stick to that in your real account as well.
First you need knowledge, then experience and then comes the luck factor. So, luck is important but only after you've done your homework.