When you get used to a workout routine, your body masters your movements and is likely to hit a plateau. Adaptation is a good idea, but at some point you need to vary to challenge your muscles. To stimulate your muscles and make them stronger, you need to establish a new strength training program.

Change your workout frequency and exercise

To change your strength training routine, you need to think about changing the frequency. How often do you workout in a week ? How many hours per session ? If you're used to doing a full-body workout, then you have a rest day in between your different workouts. In this case, you can change the frequency. This change will allow your muscles to take on new challenges and make you stronger. Also consider a new workout routine. Forget the full-body workout and do some split exercises for example. Later, you can go back to your daily routine and differentiate the exercises. On Monday you can do a full body workout and on Thursday a lower body workout and so on. You can also get more details on the internet.

Changing your exercises, sets, weights and reps

Aside from varying workouts, you should also think about changing your exercise completely. Drop the full body, lower body or upper body workout. You can do a hammer curl instead of a biceps curl. Your brain gets an alert and will activate your different muscle fibers. 
To change up your workout routine, you can also your sets. Multiply your sets and get to work. Your body will get used to it and it will be good for you. Define the number of sets you will be able to do and do it. For endurance, you might do a set of one or three of 12 or 20 reps. 
Also consider changing the weight, the resistance you use.