Im on my 3rd attempt and i can at least trll you what makes me feel like im on the right track this time...
previously i made assumptions amd shortcuts... "just focus on NCEES problems bc MERM problems too involved" or "oh a course guarantees you to pass, that should be good".
Each attempt i did same thing and not good enough.
Main focus, Practice problems... start with MERM and go from there, they are involved but get you to flip through the book and become familiar with locations of topics/formulas/appendicies/etc. Problems really helped me bc many times i said "dammit there was a exam question almost exactly like this that couldve gotten right". Im doing each relevant chapter questions twice...
SMS has good problems similar to MERM...
Many problems youll memorize the technique (pumps, mass balance, etc) and others the require you to peek at answers take ur own notes down. Id use my first run to see how many i can solve myself, peek at answers and figure out the approach... take notes. Second run i go about it with my notes... maybe third run if i feel i need it.
Finally the NCEES to gauge the involvement and types of problems. Again, take the exam at least 2-3 times until mastery.