Try to minimise muscle loss but don't get too worried about what you do lose. Your body remembers so lost muscle mass comes back really quickly when you bulk up again. Ease out of your diet slowly though when you end it otherwise you will just store fat. I recommend bringing you calories up just enough so that your energy balance is positive. If you hold it at this level for a few weeks until your body goes out of famine mode you won't rebound too much. I usually take something like tribulus at the end of a diet to encourage my body to use any surplus post-diet calories to regenerate the lost muscle instaed of fat. This works for me.

If you have recently finished a steroid cycle then the muscle you lose on a diet won't be remembered by your body. Consider waiting a while after finishing steroids before you diet. Allow your body to "accept" the new muscle mass as its own before you start dieting (if you understand what I am getting at).