Just keep practicing changing chords until you get better at it.
There's no easy way to learn.. you just have to keep working at it.
Some people progress faster than others. All I could play for the first few years was a D chord. Then for a coupla years after that the only song I knew was Song Sung Blue. (but hey, I was really lazy) Then it suddenly just kicked in when I grabbed a book of chords from an album I knew. I was already familiar with the songs so I knew how they were supposed to sound. Even then.. it was still a few years more before I moved beyond anything more than basic barre chords. (I was reaaaally lazy)