Music theory beginners are lucky. Learning music theory is a journey that can be lots of fun, and very useful. But it can be difficult when you're just starting out.
So where should you start?
-AT THE BEGINNING!!-
As simple as this sounds, most people don't do it. Here's why: They start reading, and they think, "Oh, well I already know this, I'll just go ahead and learn something more useful." And because of that, they don't get a solid music theory foundation.
If you start at the beginning and study the basics, you can get that solid foundation and learn the next steps MUCH faster than the people who didn't. This gives you an advantage over the other music theory beginners, and gets you out there learning music and getting the gigs, a lot faster.
Take a look at the Music Theory Basics page. This will give you an overview of basic articles and the main elements of music theory. Not the fine and sometimes confusing details, just the essentials.
The first article you should look at is the Music Alphabet . This gives you a firm foundation in the music notation systems and pre-develops a sense how scales will work. This article will show you how useful learning the alphabet can be. It's as easy as A-B-C!
Next, it's Scales ! Scales give you a sense of order and directionality. Also because scales are one of the essentials of music, this article will show you real life examples, not just redundant theory routines.
Then, take a look at Reading Music. Even if you don't plan on sight reading sheet music for your particular style of music, it is equivalent to being able to read written language: learning to talk doesn't require reading, but getting through everyday life (street signs, emails, this website you're reading, etc.) is nearly impossible without it. For music theory beginners, reading music helps you better understand how notes work together and how you can use them.
Looking for something specific related to music theory? Try searching for it! Hopefully this gives you some idea of where you should start if you are looking to learn more about music theory. Remember, even if you know it, start at the beginning. You may run across something you had never seen before, or read something that makes sense in a way that it didn't before.
Hope this helps! Practice hard and let me know if you have any questions!