I initially bought a few books just to contribute to Justins generous cause, but didn't really think they would be needed as all this is online after all right?... but no, they have actually really helped further my skills along much faster. Just having the song book available when you get the time to play helps a lot (get the ring bound one if you can)
On the GuitarTricks forum, you risk to get lost reading threads for hours, and forget to take some lessons! They have both open community discussions and subscriber only sections, that way you will not feel left out before getting a paid membership. In conclusion, Guitar Tricks has tons of lessons and learning material and it has hours of fun when your guitar practice is over!
Learn the difference between chords and single notes. Chords occur when you play two or more notes on different strings simultaneously to create one unified sound. These are what make up the "rhythm" portion of acoustic music. Single notes are used more for solos and occur when you play a single note at a time. Both are skills that you must become proficient in when learning to play the acoustic guitar.
Of course, this top-down lecturing is all very abstract without examples. Let me give you the worst case scenario. My school talent show, 2008. Two friends of mine performED an ambitious but utterly inappropriate Metallica cover in front of the other students, their parents and the faculty. It was excruciating. Although the solos (presumably the only thing they had bothered to practice) were technically flawless, the whole song was undone by their terrible rhythm. The timing of the song became displaced, the chords were so badly fingered that it was difficult to hear the riff and consequently the whole performance fell apart. They looked like morons. They had sacrificed learning basic rhythm and paid the price. Make sure you don’t do the same.
The layout and scope of Guitar Tricks’ content is perfect for those who want to get into a system quickly and start playing guitar as soon as possible. There’s room to grow and the content isn’t all just for beginners. However, the ideal member, those who I’d bet would be most happy with their membership, will be on the beginner’s side of the guitar looking for a time-sensitive way to learn.
Once you’re comfortable playing the chord shape that corresponds to the tab you removed, you can move on to removing the next tab, the next tab, and the next tab. Once all of the tabs are removed, the ultimate goal is that you should have a basic understanding of the fundamental concepts of how to play guitar and shouldn’t require the Chordbuddy anymore. At this point, you can remove the Chordbuddy system completely from your guitar and you’re free to explore.
Each package includes the ChordBuddy as well as instructions on how to properly attach the device to your electric or acoustic guitar. The lesson plan and companion DVD will have you playing popular songs in no time. The ChordBuddy Songbook includes over 100 songs and shows you how to play them with and without the ChordBuddy. The color-coded ChordBuddy songbook includes many hit songs from the past and present including hits from country, bluegrass, gospel and rock-n-roll genres.
Learn how to transition to different chords. One way to become proficient quickly is to learn how to transition between the various chords quickly. These transition periods are often the hardest for beginners to play when they are starting off. The more you practice between switching to different chords, however, the better you'll get at doing it in songs. Practice switching between open chords like G, A, E, and C. 
GuitarTricks.com has courses for beginners, intermediate, and advanced players. It is clear if you have never played guitar you can get started right away on this site. They start with the basic explanations of tuning and holding positions and build into various styles of playing and picking. As usual they work on country and blues first as these are often the easiest for a beginning student.
For students who have long thought about picking up the acoustic or electric guitar, this course will provide an easy-access foundation that will get you playing. When first learning guitar, it is important to have the material presented in stages, in an enjoyable way that allows you to grasp the basics of the instrument and music. The course begins simply with the parts of the guitar, the names of the strings, tuning, and technique—whether finger-style or pick. It then explores the basics of music theory with such topics as scales, triads, power chords, and fingering and shapes.
Our highly-trained professional instructors teach guitar lessons to beginners starting with the fundamentals, including scales, chords, tuning, arpeggios and rhythm. They then use famous rock songs to help guide guitar students through the early stages of musical development. Our beginner guitar lessons inspire creativity and help develop new students into world-class players with weekly private guitar lessons and group rehearsals. School of Rock's core philosophy is that the best way for students to gain musical proficiency is through performance-based music education. All of our lessons for guitar students include a performance aspect.
I've started off a new series with the awesome Ariel Posen, The Captains Privates series is popular as ever and I've also been filling in some beginner lessons of things I get asked about all the time... I'm about to re-kindle the Blues Lead 3 series which fell off the wagon somewhere and also get the gear videos rocking again... so lots in the works, lots going on and still loving it!
Surprisingly, for a free site, Justin Guitar offers a few free tools and apps to help guitarists with their lessons. The most interesting of these are the series of apps available for download on the iTunes store (so they will only work with iOS). These include a Time Trainer Metronome, a Guitar Note Trainer, and a Blues Lick app – which brings together Justin’s weekly Blues Lick series.