Work harder and don't worry about the lifts that you aren't increasing weight in. If you work other muscles groups or smaller muscles you will be just fine/ those lifts that you are plateauing in will increase do to overall increase fitness.
Also workout more; do this. Most people say they don't have time but try this. Do your daily workout and twice a day do this workout: 20 push ups. 20 air squats and 20 sit ups, two time.
Should take about 5 mins.