While i agree with most of them, i would strongly recommend against “Work backwards”. While this has helped me initially in mathematics, it took extreme effort to get rid of this habit.
Explain more why this is bad. I think it's very useful. In school, I used to say I reverse engineered a problem by finding way back from solution to the problem. Solving a problem from both ends is a reasonable way to get new ideas.
I actually used this very technique to go from struggling in undergraduate math to top 8% of my class in less than two semesters. Peeking at the answers is fine as long as you aren't "cheating" -- you just have to put in the effort to fully understand the processes and then practice applying them on your own with other completely unfamiliar problems.