As with practically any subject one must devote time to the subject to advance in knowledge and skill. This is especially true with music and playing musical instruments. There is no doubt about it; one must practice consistently to achieve skill and acumen in guitar technique. There are of course a variety of practice regimens which can be used to advance and no one way is the right way. Each person will have to determine the best practice regimen for his or her schedule and goals. Many professional guitarists devote 2 to 3 hours a day to practice. While most cannot devote this amount of time to practice, nevertheless, some practice is better than no practice.
Perhaps you only have 10 or 15 minutes a day to practice or perhaps you can only practice a couple days a week. Either way, set aside some time, as much time as possible, to practice a variety of areas in your guitar playing. Below are a couple suggested practice regimens which require 30 minutes per day. While you may of course play far beyond this amount of time if your schedule allows, this amount of time is a good basic starting point.
A Practice Regimen
Technique/Speed drill/workouts — This is sort of the “aerobic” element of your guitar workout. Devote about 10 minutes to this area. Work on scales, modes, stretches, etc. for a full 10 minutes. You will need a metronome. Part of speed and strength training involves developing good technique. You may be fast but if you are sloppy then it does not mean anything. So get a metronome and work on your technique and speed all while developing a better sense of rhythm.
Reading/Theory practice — This is sort of the “vegetables and protein” portion of the regimen. Either work on your reading abilities trying new and challenging pieces of music or devote some time to music theory study. Continue to develop your knowledge of music theory; it will make you a better player! Devote another 10 to 15 minutes to this portion.
Song/Fun practice — Use your remaining time to work on favorite songs or try something new that interests you. Perhaps you want to monky around with a slide guitar piece or try some odd tuning, go ahead, have some fun!