The best thing to do is to start a healthy diet and exercise program with reasonable results. Healthy goal is about 2 lbs a week, anything more would be starvation which can led to worse problems. The easiest way to cut calories is to find alternatives to the unhealthy things that you drink and eat. Cut out the junk food completely, just a few snacks every once in a while. Cut out all soft drinks and DIET DRINKS, these are just as bad a regular non-diet sodas. Drink lots of water to flush out the body and keep well hydrated, this will result in gorgeous skin as well, distraction from a few extra lbs
ALSO, WEIGHT IS NOT AN ACCURATE MEASUREMENT, YOU SHOULD LOOK AT YOUR SIZE AS A MEANS OF CALCULATION. MUSCLES IS GOOD AND WEIGHS MORE THAN FAT!!!
Changing up your diet and exercising programs also helps you kick the plateauing, especially if your building muscle. If you don't adjust your exercising so that you are pushing your new muscles then you won't be able to build MORE muscle, you will simply keep what you have already gained.