The first mistake is overcooking the pasta. When baking pasta, it must be cooked in water until al dente , because baking will continue to cook it. If you start with already soft pasta, the final result will be mushy and unpleasant.
2. Using too little béchamel or too much seasoning
Béchamel sauce is essential for adding creaminess and binding all the ingredients together. Often, too little is used, risking dry pasta. At the same time, too much sauce or cheese can make the dish heavy. The key is to find the right balance: enough sauce to coat the pasta without overpowering its flavor.
3. Not gratinating properly