At some point, your page begins to look pretty much the same from day to day. It is not bad. But it is not getting noticeably better. And for a beginner, that can feel quite frustrating. Here you are with the pen in your hand, doing drills and spending time, but you just do not feel like you are improving. In calligraphy, when you hit this kind of wall, it usually does not mean that learning has stopped. Rather, it means that you have been practicing so much that your own errors are now invisible. Improvement begins to happen again when you stop practicing what feels fine and start studying what you are doing quietly wrong.
One of the most common causes of a plateau is practicing too many different things on one page at a time. You warm up and write out a few different alphabets. Then you make a couple of flourishes here and there. A short phrase goes in at the bottom of the page. Nothing on that page is receiving enough attention that it will begin to improve on the next page. When a mistake can hide inside a range of different practices, no change is ever likely to happen. A better way to practice during a plateau is to choose one or two things on a given page that need attention, and only write those for a week or two at a time. If spacing is still uneven, then make the main focus of the session improving that. If downstrokes still look dark and hard, spend that session focusing on the shape you are getting by adding pressure. If your letter shapes are drifting away from a given line, spend the session only on that one problem. It may seem repetitive, and at times annoying, but this kind of focused practice is exactly what the hand and eye need to continue making progress.
Even when you do not have a professional mentor available to give you feedback, it still helps a great deal to give feedback on your own. This means do not just look at a page and ask if it looks nice. Instead, look at the page and ask, Is my oval really closing up completely? Are my ascenders all the same height? Do all my counters look about the same size? Is my line straight or does it move gradually upwards? It is easy for a beginner to simply judge a word as a whole. And if that word does not look nice, there will be that feeling of failure that nothing specific is really being accomplished. This, of course, makes improving those issues almost impossible. Instead of doing that, choose a letter that does not look good, and look at the one letter that looks best. What are you doing differently there? How can you try to copy it on the other letter? When you are no longer just searching for perfect looking results, but searching for the patterns in those results, reading through a page becomes far easier.
Another thing to try is slowing down or speeding up the pace at which you are practicing. Sometimes plateaus exist simply because we have been practicing at one speed for a very long time. If we always write very slowly, it is quite possible for our letters to look stiff and contrived in appearance. If we only ever write very fast, the same carelessness is likely to remain forever. Try writing the very same line one time at a much more controlled pace, and pay very careful attention to how the pen is moving at each point. Then, write that same line a bit more freely, but be very careful not to change the shapes at all. This will give you a great deal of information. The letter parts that collapse under stress will reveal themselves, and those are the parts you need to focus on the next time you practice. You may not have a plateau break until you change a little of what you are doing with every practice session.
A helpful routine when your practice has come to a complete halt is very simple. It only takes fifteen minutes. Spend five minutes going over a basic stroke that still feels a bit difficult or unconfident. Spend five minutes writing out a letter that goes with that particular stroke (if ovals are still a challenge, practice out c, a, d, and g. If upstrokes are not feeling confident, try i, l, b, and h.). Spend the other five minutes on a very short word containing letters that use that particular stroke that you have focused on and write that word a few times, trying to achieve that one thing you want to work on. And if nothing looks any better, do not say nothing is changing. Compare your first attempt to your last one. In calligraphy, improvement often happens quietly and incrementally. It is possible for an individual letter stroke to appear more even and smooth even before the letter itself has improved. A word is possible to begin settling onto the baseline even before the spaces have started to look much better.
And finally, when you are practicing, you may feel like it is a plateau because you really do not know how well you are doing. There is a reason this is so often the case. If you have an older practice sheet lying somewhere, try comparing your work to it. Every few weeks, put the page you are most proud of and the page you were the least proud of side by side on your desk. If it does not feel very different, do your best to look at it in comparison to work you created two or three weeks ago. This helps because your learning is occurring through accumulation. Your hand is learning through thousands of small, invisible shifts over time. And when your practice feels like you are just writing one thing over and over, more decoration or longer pages is not the answer. It is a simpler question, smaller drill, and a better look at the truth of where you are.