how to lose weight in 30 days?

i want to lose some weight,i have tried the cutting down on food and exercise but i never followed through because i don't have a lot of time.i way around 154 pounds and would like to drop about 20 pounds, i don't even know if its possible in such short time but if you could help me out that would be great,i have an event in 30 days and would like to have the weight lost by then