As stated above, get as much of your braking done on approach. I tend to shoot for a slightly later apex, avoiding the rumble strip if possible, and I always maintain some throttle under braking so as to not have all of the car's weight shift forward as it would under brake application alone. Weight moving forward unsettles the rear, an unsettled rear likes to spin. I also generally run rear-heavy brake balance (when I'm adjusting the proportions from their default 1/1) on rear-heavy cars as it, too, helps to keep the nose from dipping quite so much.
Other driving techniques apply with MR as well, and are perhaps even more important. If you're neither accelerating nor braking, you're not going fast enough. Sudden unnecessary changes in brake or throttle (as in getting into either too much too soon necessitating reduction) only serve to destabilize your car and reduce the amount of grip at your disposal.
Look to long wheelbase MRs to dip your toe, the Honda NSX is a good candidate and so is the [much more expensive] Pagani Zonda C12 (not the C12S or the C12S 7.3, too unwieldy without experience). Good luck, the cars are very rewarding once you figure them out.