Take a bobby pin or a paper clip and poke it through the knots in the string. This should allow you a little space to be able to untie the knots the rest of the way with your fingers.
You could use hot glue or double-sided tape to attach the string lights. Add a small bead of glue onto the back of the lights and stick them individually to...
That actually means that you can press the other string on the third fret and tune the string you want to tune to the same tone. To be more specific:...