Hello. I was playing electric guitar 7-8 years ago but I sold it compulsorily. Now, I bought a new guitar and I don't know almost anything. I can play the basics. Some chords, simple solos. I forgot note reading, I will learn again. So, what should I do in order? (I mean techniques, rhythms etc.)
Well, since you can remember some chords and easy solos, work on getting the chord changes underneath your hands again and practice the solos slowly (preferably with a metronome or Guitar Pro or something).

If you want to get back into reading sheet music, you can easily get a Real Book (for jazz tunes) or trying searching for some of your favorite songs (artists, video games, etc) on MuseScore's website or something. The good thing about taking the Real Book route is that it'll give you a reason to learn some more extended chord voicings and the theory behind it on the guitar.
Skip the username, call me Billy
Practice scales. Also, try to transcribe simple Christmas song melodies to the guitar, like 'We Wish You A Merry Christmas' and 'Silent Night'.

The first technique will help you get comfortable with notes in the scales so you can better improvise solos and arpeggiated passages.

The second technique will help you train your ear to detect intervals between notes and their relations to the fretboard, and will also improve your sense of melody.
Last edited by durrrrlicious at Nov 30, 2016,
Scales and arpeggios would be good to get under the belt again. Then just playing through your favourite songs will be good practice too, but I think you'll be amazed at how much you will pick up again due to muscle memory. It's like riding a bike