Playing the guitar should be something you enjoy, especially if you want to become an experienced and respected player. You should always look to learn using a combination of established study materials (such as books recommended by your tutor/a friend) and by playing music you enjoy playing and to which you enjoy listening.
When practising, you should always start by warming up on a piece and some scales you have recently mastered. By doing this, you will remind yourself that you are progressing. When you move on to a new piece/scale/exercise, ensure that you always tackle one measure at a time. Do not move onto the next part until your confident you've mastered the preceding sections.
Technique is definitely the most important aspect of improving your playing. When practising, many students spend time haplessly moving from the start of the song to the end, without paying any attention to the way in which they are playing. This will not succeed in improving your guitar playing ability. It is far more beneficial to pay attention to your left and right hands' techniques and do not be distracted by the sound of the study. If your technique is solid, the notes and music will take care of themselves.
By sticking to this advice as a beginner, it will eventually become second nature, allowing your body to adapt to the guitar and making intermediate and advanced playing far easier. In other words, the more work and patience you put into the basics, the quicker you will improve, maximizing the enjoyment you get out of your guitar.
Once the difficult beginner stage is past, try playing with other musicians to gain better knowledge of improvisation and rythym. You will not only be helping yourself but also the other musicians with whom you are playing, which is very enjoyable indeed. Perhaps you might think about starting a band or solo project at this point. A great move which will not only improve your playing but could also improve your confidence and creativity.
Sure, all of this will take time but trust me, the years and years of wrong notes and quiet, personal practice will definitely be worth it 3 or 4 years down the line.
