How do I do it?

Try looking into the South Beach diet. Even if you just do it for a month or so religiously, it will certainly help break through the plateau.

When we hit a plateau, it's our bodies' way of telling us that it's comfortable with our current routine. It likes the way we're eating and how much effort we're expending when we work out. The only way to bust through that plateau is to do something different. My usual suggestions are to change the makeup of what you're eating (eating less carbs helped me through my most recent plateau) or upping the duration or intensity of your workouts. Even just changing what kind of exercise you're doing can help. If you currently walk, try adding in some jogging intervals. If you do the 30 Day Shred, try P90X, or biking or swimming.