LATS advice was good, my guitar teacher also taught me that it's good to sit in front of a metronome and strum chords, if you have a standard 4/4 beat you can strum along to the metronome and also pull triplets and doubles with the beat to kind of get a hang of it. Also you may think that you can change really smoothly but if u do that with a metronome then your forcing both hands to keep in time and it's suprising how u realise that even if your fretting hand is half a second off it can relly screw up your picking hand.

Whenever i'm playing chili peppers songs and it gets to the open chords and bar chords i don't usually strum along exactly with frusciante but rather improvise a bit and just feel the beat of the song, make it your own! as long as you're playing the right chords and you're doing the transitions at the right times then you can experiment with strumming in different rythm to the recorded version of the song.