Don't forget that there will be plenty of questions that are more subject content than plug and chug equations (I think my exam review guy said it was about a 45/55 split). Many of the subject matte questions will require you to either understand the topic or be able to find the answer in one of your references or the CERM. These are the 'equalizing' questions, the ones where you will probably spend a minute or two on since you will say 'topic xxx, oh yeah, that is in the CERM chapter regarding yyy'
Like many of us have said, understanding the steps and how to get from step 1 to step 3 is what is the most important.
Being able to identify the question in front of you is huge... if you look at a water resource question and can say 'I need to use Mannings here', you have already done 3/4 of the work, the rest will be plug and chug.
Don't be afraid to reverse-engineer a question. Rather than iterate a calculation several times, you can work backwards if it is a tough equation to solve - just plug in the answers and see what ends up being the closest.
-Ray