Three approaches to develop studying skills are:
1.Have a passion for the course or subject of study by being ready to apply its lessons and teachngs to practical problem society aruound you.
2.Create specific time table for time management in a 24 hr window between, official lectures as well as personal studying time.Recreation or games or break will add to variety and better results than studying 100% of the time.indoor games, discussion group within the class, excursions are all allowed as break input and variety.
3.self evaluation helps to assess one's readiness to answer examination questions in a disciplined time manner.
4.I believe also in prayer asking God for direction in where to concentrate.It has helped me and you too can benefit from this if you can communicate with God.If you cannot you can buy my book, Life is very good' on www.amazon .com to help you develop the skill.Good luck.
I think the most important thing is to really understand what subjects you know bad. Thus, you can make more efforts in preparing those projects that will help you develop your "weak" skills and fill in the empty knowledge gaps. Also, this may be trivial advice, but I recommend reading books. In this way, you learn to formulate your ideas in an interesting way, and this is an important skill in terms of studying. And, of course, don't be afraid to use reliable online platforms. For example, on https://educat.tools/, you can monitor your gpa or calculate the time for your speech (that will clearly help in preparation and make your performance better)
It seems to me that the most important thing is self-responsibility, because if a student is irresponsible about his own learning process, then there will be no result.