Yes, in order to get constant results with calisthenics or any other type of training you must progress continuously according to science. 
The process is called progressive overload and it’s one of the most important factors that helps with muscle ,strength and overall skills development. 
Here’s exactly what to do in order to progress with your workouts and become bigger and stronger. (according to science and my personal experience)
What You Will Learn
- How workout intensity and progress works (explained)
- How to progress with extra resistance (weights and resistance bands)
- How to progress with different exercises (more advanced variations)
- How to progress with rest time and volume (best methods)
How workout intensity and progress works (explained)
Workout intensity explains how difficult it is for you to complete a set of any exercise or whole workout. It works parallel with progress because if something is easy for you, you must increase the workout intensity in order to progressive overload.
To understand if you currently have enough workout intensity and volume simply ask yourself these questions:
- Was it easy?
- Was it very difficult?
- Was it very tiring?
- Can I do more?
- How do I feel?
If your honest answers tell you that you can do more and you haven’t reached your limit (without sacrificing proper exercise form) then you need to step up things a bit.
In case your main goal is muscle mass and strength development you should focus on doing 6 to 12 reps for every single exercise according to science in such a way that you can barely do the last repetition. (and still preserve proper form) 
Here are the most popular ways you can use to increase workout intensity and volume in order to progress and keep getting results (I’ve tried all of them):
How to progress with extra resistance (weights and resistance bands)
The most common and easiest way to progress with bodyweight exercises is to simply add resistance once you can do more than 12 repetitions with proper form in a certain exercise.
The most common ways to add resistance for bodyweight exercises are:
- To wear an adjustable weighted vest (link to mine)
- To wear a backpack filled with heavy things (not very comfortable but still works the same) – you can use bottles of water, sand
- To use resistance bands (link to mine)
Example: In your last workout you did 15 push-ups for your last set and it felt like you could do a couple more. To make them harder (increase intensity) you can wear a weighted vest, use a resistance band or carry a backpack with 10 lbs (5kg) of water bottles for your next workout.
How much weight/resistance to add?: Simply add a bit of weight (10 lbs/5kg) and test. Is it too light or too much? Can you do between 6-12 repetitions without losing the proper exercise form? If you can’t remove/add weight and try again until you find the sweat spot. Write down somewhere that number and aim to improve it with every workout you do.
How to progress with different exercises (more advanced variations)
Another very effective way to progress is to simply do a harder variation of the previous exercises and make it a lot more difficult so you can do between 6-12 repetitions.
Example: I can easily do 15-20 dips at once. In order to make them harder I can simply lower myself even slower and hold down for a second on the lowest part (the most difficult place) then push myself up. Now I can barely finish 12.
How to find more difficult exercise variations?: The best way is to think a bit. What can I use/do in order to make this exercise harder? Slow it down, hold on for a second in the most difficult part, use gravity as an disadvantage? Try it out! If you can’t think of anything don’t worry. Go to Youtube/Google and look for harder alternatives. There is almost always a harder variation you can do.
How to progress with rest time and volume (best methods)
According to science you should rest 60 to 90 seconds between exercises and sets for maximum muscle growth and development. .
So in order to progress with your workouts and get maximum growth a great way to increase intensity is simply to lower your rest time with 15 to 30 seconds.
That will cause you to make your workout 1-2 minutes shorter but if you are doing everything the right way that difference will feel like a completely new workout. (which will stimulate progress and growth)
Example: You follow a regular workout plan and you rest 90 seconds between the supersets. But you feel like you can do more. Next time lower your rest time to 60 seconds (30 seconds less) and try it out. I bet it will be way harder to complete. (which is a good thing in terms of progress)
Now you know how to progress effectively and why it’s important to do it regularly.
Final Tip: Don’t forget to keep track of everything in order to go only in the proper direction. Use a notebook or an online document where you take a second to write down your current weight/resistance used, rest time and number of reps after every workout you complete.