When I was studying guitar pretty much full time, I had to learn several lines and licks per week, besides learning sight reading, theory, etc. Once those licks and lines are assimilated into your playing, it broadens your playing 'pallette'.
For example, try learning one lick every week. What you do is play something that has a challenging line (I find Miled Davis and Charlie Parker great for these types of exercises) and learn the lick by ear. Then spend a week memorizing it. By the end of a year, you will have added 50+ licks to your mental amoury.