I would really like to learn theory so that I can do things like making my own chords, know what scales to play and where when jamming with another guitarist, know what key songs are in and what I should play in and what chords sound good together etc. Basically I'd like to learn a lot so that I don't need to play other people's stuff and can just pick up my guitar, improvise and come up with something different and interesting. At the minute my solos all sound the same and when i try writing a song its either power chords that sound like generic pop punk or open chords that all sounds very similar.

Any help would be very useful thanks
Well, just start with the basics. Research it up on online. Theory has more to do with just playing your instrument, it also has a lot to do with reading music and knowing composers, and key signatures and stuff like that. Though basically, just research up online, or go to your local library. Nobody can really teach you online, unless you have instructional videos.
musictheory.net is a great tool for learning cadences and scales, and can show you using sheet music, which is great if you can read it. however, if you look for The Crusade column on this website, they helped me severely, and related it back to guitar instead of piano like musictheory.net does. both are great, so I suggest reading both of them equally. cyberfret.com has some theory lessons too but they werent as great.

EDIT: http://www.ultimate-guitar.com/search.php?value=crusade&search_type=columns click that to find the crusade articles. they arent in order, so just find which lesson number you need and go from there
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Last edited by Zinnie at May 20, 2010,
^ Musictheory.net is great, highly recommended

A quick and simple tip to help expand your chord vocabulary is slash chords, they are chords that are written like D/F# or E/B, what makes them unique is that they're fundementally the same chord but the root note is replaced with another note, usually, within that scale.

E.g. Take a normal D major chord

D, F#, A

2 (F#)
3 (D)
2 (A)
0 (D)

and instead of using the open D as the first note, why not change it to something else? Just pick a note from the Dmajor scale and replace the bass note with something else.


2 (F#)
3 (D)
2 (A)
4 (F#)

Still a Dmaj chord, but it with an F# in the bass to give it a different sound.


2 (F#)
3 (D)
2 (A)
0 (D)
2 (B)

Again, still Dmaj, but now you've added a minor 6th into the mix. There are many possibilities and some simple changes can open up a lot of new doors.
Yes there are a lot of free theory lessons on the internet. However, learning from books or reading information off the internet can be confusing as hell. So many times after I learned something from an actual person, I go back to the books and think "why did you exlpain things the way you did?" (sometimes important information is left out assuming you already know it) I took music theory classes at a local community college...I struggled with a lot of the information as I had never taken music classes in public school. I took a hour lesson with a jazz guitarist and I was able to understand things better than most of the students in the class. Online lessons are only going to address things a certain way. Like me,...you might have a simple question over a simple detail that can really hold you back. Where as with a teacher you can simply ask that question and in a matter of minutes the problem is resolved. I've seen a lot of people struggle over what now seems simple, but that is only because it was explained to me more clearly.
MARTY FRIEDMAN--"It’s a lot easier to be technical than it is stylized; it really is... But I think it’s a lot more rare to have someone who’s really got their own sound because that’s something you can’t practice."