They best way to learn how to play over chord changes is to practice improve.For this ex. what I do is give myself a certain chord(s) and develop a melody or guitar lead and work it around the progression. In this example, I use Aminor,Fmaj.,Gmaj.and try to follow along with the changes.It is good practice! Again,it does wonders when trying to build up a vocabulary that you can call your own.for best sound results set to AcNylon.