Perhaps you meant to say something different, but Liposuction is not typically done to achieve a breast "lift". Liposuctiion can be a way to reduce the size of your breast, but one the biggest drawbacks of this type of reduction is that it produces very little in the way of a lift. If you are truly looking for a breast lift, then you might want to consider something other than liposuction.
If your goal is more reduction, then the best way to prepare is to eat a health diet, avoid aspirin and non-steriodal pain medications in the two weeks prior to surgery, and be as close to your goal weight as possible at the time of your surgery. Significant weight loss after surgery could result in some sagging of your breast.