One of my students several years ago had a recital piece that the rhythms between the left hand and right hand were really hard for him. As I had done with many of my students I told him to try what I called "lap-slap" the rhythms. So you take the rhythm of the left hand and the rhythm of the right hand and you slap them out on your thighs VERY SLOWY while saying something like: right - left - together - left etc. Then you gradually work up to full speed.
So this year his recital piece has four different sections with very complex rhythms. So he tried the "lap-slap" technic and again it helped him a lot.
Here is an audio of Joe first demonstrating the four different rhythm sections and then playing the entire piece.