Yes, it sounds boring and like the kind of thing only music geeks like doing, but playing scales is really the best and easiest way to get to know written music.
So you understand the basics (as outlined in the previous series of posts: Reading Music for Guitar Beginners. Now it’s time to put this knowledge into practice.
It may sound too good to be true, but once you understand these basics, “learning to read” is just a matter of practice, practice, practice.
It's no secret. The more you practice with written music, the more you will understand and become familiar with it, and the more you will understand how it can help you with your guitar playing.
For a description of some practice tips, check out things to do before beginning serious work on scales and songs.
Most new guitar players will begin with the C Scale because it has no sharps or flats and has you going from A3 up to B1 (and another octave up to E8).
Here is a simple exercise for the C Major Scale starting at A3. Here is one of the C Major Scale going from B1 to E8 (high E 8)…
The best way to practice these and ingrain both the note positions on the staff and the physical positions on the fretboard is to say the notes as you play them.
Two more relatively easy scales, and commonly used in songs are G and D…
Another very popular key is D. Here is a D Major Scale Exercise starting at D0.
Practice these scales on a regular basis and soon “reading” will become second nature.