How do you spend that 30 mins. practicing? Do you just play songs? Practice time should be a balance of physically challenging finger exercises and scales to build technique and melodic playing to improve your musicianship. Musicianship is not athleticism but for an athelete to make greater gains s/he'd supplement playtime with time in the weight room... and you really need to put in more than 30 mins/day , at least an hour... preferably 2 hours/day. When I first started, I'd put in 10-15 hrs/day because I really sucked and I really wanted to play guitar well . If you only have an hour, for example, try 15 mins. hardcore finger exercises, 15 mins. scales, 15 mins. songs you like to play and 15 mins. improvising melodically (important so you don't sound like a machine playing mindless scales .) Have a metronome and some sort of timer device. Other's might disagree but this type of regimented training is quite efficacious IMO.