It totally depends on you whether you opt for crash course or self study.

You should choose according to your comfort.

Make sure you brush up your concepts and do revise all the syllabus and focus on the topics which carries more weightage in the exam.

It is important to join test series as it will help you to understand the actual enviorment of the exam and you can analyse your preparation level. You will get to know your strength and weakness. So, that you can work upon them.

All the Best!!