Becoming an Experienced Researcher and Writer in any Field or Discipline takes A great Deal Of Practice
If you wish to become an experienced writer the only recommendation that is applicable is "practice". Becoming a better writer is about writing every day and working hard to do your best work every time. The same could be said about doing research; most formal writing requires some amount of research and learning how to do research correctly and cite sources, as well as weed through examples, takes a lot of application and practice too. When you first begin your academic career it is very likely that you won't have much experience doing in-depth research and may feel a bit overwhelmed. The good news is that after four or more years of college or university you will have mastered the skills required to become an expert writer and researcher in your given field of choice.
The whole point of attending College or University level courses is to learn how to do things as the experts do them. You may not realize it now but all those "long writing assignments" and "tough grading" is meant to prepare you to be an expert in your field. The reason why instructors press students so hard is because they want them to learn how to do things correctly so they do not flounder in the professional world. You may think that you won't ever mater the writing and researching process now, but you will as you begin to take more classes and learn the tricks, and tips that make writing research papers easier.
The most important thing to keep in mind is that you aren't expected to be an expert researcher on day one. It is going to take a lot of application practice before you learn what makes good research content, and how to sort your research so that you only use valuable resources. The entire point of enrolling in post-secondary education is to learn so don't get detoured if you don't do well on your first few academic writing assignments. Keep on working at it, and doing your best to create a fantastic writing assignment. Eventually it will come easily to you, right now you just need to practice.