First just strum the chords slowly. Make sure your fingers are placed properly and firmly behind each fret. Make sure that the strings your not fretting are not being muted by you other fingers. If you're fingers are arched that seems to help a lot.
Use only the pads of your fingers to press the strings down. Take your time... have fun... and PRACTICE!!!!!!!!!!!!!!
Play these chords slowly back and forth until you can change between them smoothly. Don't rush.
Try inserting this chord in....