First, it is possible that your paper is related to this. Sometimes glossy paper is used, no matter how you write it, it seems that there is no strength. In fact, in the process of writing, the paper does not form resistance to your pen, which makes you write easily. Therefore, it is recommended to use better paper. If you are a beginner, you can use draft paper. If you want to use Xuan paper, you can read the article "Top Ten Xuan paper brands (with the types, choices and contents of Xuan paper).
Second, maybe you have a poor foundation, that is to say, you don't have a systematic copybook, or even if you have a copybook, you don't have the guidance of a professional teacher, which leads to the lack of strength in words and seems to be floating. Regarding copybooks, I suggest you read How to Choose Brush copybooks for Beginners' Calligraphy (with the names of 46 classic copybooks). Many of the copybooks here are excellent. I hope it helps you.