I think the most important things in mechanics are:
1. Always redraw diagrams, show ALL forces, most mistakes are made by not recognising all forces, the visual aspect is crucial for any mechanics paper.
2. Write down any information the question gives, this may help you visualise the problem better (especially with suvat type questions). Also, any formulas revelant to the question you can think of.
obviously you don't have to, thats just my personal experience on where i've made mistakes. M2 is typically an A2 Maths exam and one that single maths students don't look forward to.
good luck everyone