I’ve always associated anything too light weight with feeling cheap. After that, it’s what the neck feels like. Are the frets rough and noisy when you bend? Can you feel sprout? Does the fingerboard feel like there’s just a bit too much friction in the grain? Does it feel like you can cut yourself on the fingerboard edge? If so, it feels cheap. Is the neck set arrow straight with low action and no buzz? If not, it feels cheap.
Then there’s the guitar’s acoustic resonance. If a guitar resonates deeply and still has good snap, it will sound well made to me, regardless of how acoustically loud it is. If it honks and kaws like it’s made of hollow out plastic, it’s going to sound cheap.