INTONATION: consistency in tune up & down the neck
Ensure guitar is in tune. Play a chord & then play its higher fret version. Both should sound in tune & have the same tones.
Example: C chord
ACTION: height of strings from fretboard
Play a few notes & chords on different parts of the fretboard. Fingers hurt? Action too high. Buzzing sounds? Action too low. Choose one with low enough action for ease of fretting but zero fret buzz.
Hold the guitar side-on. Check that the body is flat. A bloated body can affect action & intonation.
Test the tuning peg for every string. Ensure that they are not overly tight or loose. Loose pegs can cause strings to go out of tune easily & give off rattling sounds.
Hold the guitar side-on. Check that the neck is straight. A bent or warped neck can affect action & intonation.
Check that there are no hairline cracks at the junction. These cracks may deepen overtime due to string tension causing warp & fracture.
A guitar’s looks has little correlation to its sound. But having an insta-worthy guitar could encourage you to pick it up more often.
Guitars come in slightly different builds. Choose one that feels comfortable in your arms.