Here are a few things that might help in your quest for smoother transitions between chords:
Look at the two chords you are moving between and see if there are any notes or strings that are the same in each chord. For instance one of your fingers may only need to move one fret on the same string. If this is the case then you do not really need to take your whole hand away to change chords. You can lock in the finger that needs to move the least and then use him as a sought of anchor.
However if the chords you are moving between are completely different placements then you may want to take your hand off change shape in the air and then try and place all fingers on at the same time.
Another tip is to keep strumming in time even if you haven't locked on the chord your changing to. This is a deceptive trick that makes your playing sound better than it is.