Playing both hands in perfect unison

Hey,

Does anyone have any tips or advice on how to practice getting both hands to play perfect in unison on a snare drum so that there is no flaming?

I seen Gavin Harrison cover it very briefly in an interview but he didn't go in to detail.

Iv'e searched on line and looked on here but it doesn't seem to be covered. Any advice at all is appreciated.

Cheers.

Playing both hands in perfect unison