Do The Do Re Me
You remember the old do re me in grade school and thought it was cheezy and you said to yourself, I don't need to learn that it's not for the guitarist especially the Rock and Roller. When I started my first year at Berklee College of Music, I got a good taste of it in my ear training class. I had to get in front of the class and make an fool of myself singing do re me fa sol la te do.
It took a couple of weeks but I got the hang of it and it really helped with my ear training. Most self taught guitarist like myself put on a song a learn it, then memorize it. If you work on your ear training you can learn your favorite songs in half the time. Try this out the next time you practice. Hold a C note on the 3rd fret 5th string and sing (Do) now image what the next note in the C major scale will sound like before you hit it. This will be D (RE) do the same with all the notes until you reach the octave.
Below is the notes in a C major Scale
Once you get the hang of this, sing a simple guitar riff in your head and see if you can write down what notes are in it. If you practice this enough you will get great results.
Hope this helps