For anyone who has tried to learn guitar before and not quite picked it up, this is your calling. There is nothing more important then to practice practice practice when you first start out. And as those of us who picked up a guitar before Rocksmith will tell you, it's tedious, uninteresting, and unsatisfying at best. This game actually makes it fun to put in the time and effort. Your fingers aren't used to moving around the fretboard. Your brain isn't used to seeing (or thinking) of notes to play and then actually doing it on time and on rhythm.
Keep putting in around an hour a day in this game and you will start to see the difference in no time. I recommend you get the RS1 Import through Steam and the PC/Mac version also has loads of customs. Give this game a shot if you haven't already.