These free music theory lessons are designed to go along with all the scale and chord/chord progression lessons you can find on this site.
You can simply go through them in the order you find them below or just pick something that you are interested in learning and go from there.
Most of these free music theory lessons contain a free PDF download that contains the actual tutorial. The best thing to do is to simply print out the PDF files and read them each a few times to help the material sink in better.
A lot of times you will be given a system to follow in order to help you internalize the theory concepts and you will basically need to practice those "mental gymnastics" until you know the material well enough that you hardly have to think about it at all.
The main thing to remember with these lessons is that you want to be able to drop any methods you use to figure out the theory material because you are simply familiar enough with the material that you know everything without needing to figure it out anymore. What????
For example, in the "Understanding Keys" lesson below I will teach you a quick method that will enable you to figure out any major key in your head. That is great, but any method requires you to think a little bit. What the overall goal though is to eventually use the methods taught enough that you simply know the notes of say an A Major scale without needing to use a method to figure them out anymore.
I liken it to the way many business men or women have a certain way of categorizing the names of people they have just met. If they hang around those new people enough they aren't gonna have to go through a little mental routine whenever they want to remember a person's name, they will simply know their name without thinking. That is what you are aiming for in these lessons.
Hope this makes sense! Enjoy!