Please give a few tips and tricks to crack the LMRC CRA exam

You need to finish three sections of LMRC CRA Online Exam within 120 minutes, which means you need speed with accuracy in order to attempt 140 questions in total. The more you practice, the better chance you have of acing this exam.
Make mathematics and reasoning your strong subjects, practice questions to solve them within time to increase efficiency. You should lay emphasis not on mugging up the formulas but instead try understanding the concepts, so, you can modify the formulas according to the question requirement.
Remember negative marking is a factor here. Therefore, try not to attempt questions that put you in doubt.
Manage your time properly; give appropriate amount of time to each section. Try to improve your time by practicing as many online tests as possible. Youth4work provides online mock tests will time limit attached to each question; this way one can learn to finish the entire exam within the time limit.
You Tube: https://www.youtube.com/watch?v=8L7Y44rLA3k&t=3s