Definitely music theory is the way forward, working out those sweet chords is the key to making a phat bassline and a catchy hook. After you know something about chords, you need to work on getting the hooks spot-on, because the hook is the part of the tune that stands out the most. then use your chord knowledge to make a bassline that complements the hook and makes the track shine. Or the other way around, first a phat bassline, and then a catchy hook to complement.