Build strong fundamentals on the guitar/bass either acoustic or electric so you are well-equipped to play in any genre. 

Develop your left hand (fretting hand) as well as your right-hand (plucking/strumming hand) techniques for either the guitar or bass to enable yourself to play that challenging Funk, Rock or Country tune  or even a classical tune.

Acquire the ability to read standard music notation and tablature for the guitar/bass for a steady foundation in your musical journey and equip yourself with adequate music theory to provide the ability to write original music, expand your creativity and learn to improvise on the instrument.