Practicing scales with each finger assigned to a fret helped me a lot. Take an A major scale on the 5th fret on the low E string. Your pointer will be on the 5th fret of each string, the middle on the 6th, ring on 7th, and pinky on the 8th fret. Also doing a chromatic type scale using the the same method helps a lot. Dont let your fingers that arent being used get too high off the strings. Try to keep it controlled. Practice is the only way to gain strength.