learn to properly tune it, practice de-tuning then re-tuning it.
Also practice re-stringing it and properly stretching the strings. nothing sounds worse than an out of tune guitar.
To work on dexterity and getting those callouses nothing is better than this simple exercise:
Starting on the low E index finger on fret 1 alternate pick and put down the next finger on fret 2, up to the pinky on the fourth, then go up the 5th string and so on. Once you get to the high E shift your pinky to the fifth fret and go backwards. Pinky down to index ending on the second fret. move down the strings to the low E and shift up with the index now starting on the third fret.
Work your up the fretboard to the 12th, and then work your way back down. Remember to alternate the pick up - down. Once you get fast with that you can try doing it skipping your middle finger. Then skip the ring finger, try all variations.
good luck, have fun!
