I have also used Justins program in app form He is a great teacher I started with guitar tricks about a month ago.

What I did was look at the lessons and if I knew the material moved on to the next lesson I spent my time learning guitar fundamentals 2 and learning the songs that are recommended for guitar fundamentals 1 and 2 I like the fact that they have a play along .and jam tracks with a real band not gpx This gets you used to keeping a steady beat without it getting boring I can also play through whole songs as opposed to part songs

The other thing is every teacher is different so if you go through the recommended songs you will find an instructor whose teaching style you prefer by the way they teach the song For me its a tossup between two of the instructors . I am concentrating on acoustic for now

Hope this helps