Just jump in and get your feet wet! Start small with a simple design and work your way to more advanced designs.
Check out Kicad on the internet. It is FOSS, has a large user base, a large parts library and is easy to learn and use. It has integrated schematic capture and PCB layout software and comes with plenty of example designs.
I have completed numerous designs with it, and a friend has done at least a dozen production designs with the package.