Originally Posted by: Sore.fingersHowever, when playing melodies, I wonder if it isn't better to fret notes at an angle all the time.[/quote]

The general principle is to use the most natural & efficient finge placement & motion to play any series of notes & chords. That can be a different angles depending on the musical passage. But to be clear it is just the tip of of your finger (last knuckle joint to finger pad) that really needs most often to be more perpendicular.

In general, whatever you need to do to make the music happen is fine. Just be careful not to paint yourself into a corner by making it harder to get to the next note, chord or phrase.

[quote=Sore.fingers]Should I only play with angled fingers if I want to mute an adjacent string and perpendicular if I don't need need to mute adjacent strings?

It really depends on the musical passage you are playing at the time. Often for beginners playing chords you are trying to let open strings ring, and or, lower fretted notes ring. And the biggest cause of muting them is interference from the tips of fingers that are too angled!

This tutorial covers muting as mentioned by DraconusJLM.

https://www.guitartricks.com/tutorial.php?input=2281

Hope this helps!