I took the exam first try and passed in October. For me it was practice, practice, practice and tab, tab, tab. In addition a big help was the "Useful Equations for the Civil PE Exam for the HP 33s and 35s". I took the NCEES practice exam about 4-5 times spread over a couple of months and used it to ensure that I had adequate references to the CERM and codes listed for each problem, as well signed up for the PPI Exam Cafe and took who knows how many sample problems.
In addition I programmed all of the useful equations in across my 2 calculators, and practiced with those to ensure I could look up the equation quickly and flip to it (I also wrote in equation number references in the NCEES practice exam and my other materials to cross link).
I also did the online on demand School Of PE course, but watched the videos mostly in the background as I was tabbing things and cross referencing their notes and the useful equations/NCEES practice/CERM. completely skipped the structures and foundations/geotechnical lectures as I knew that anything I didn't know was going to be a steep hill to climb and my efforts could be better focused elsewhere.
Test day I showed up with all of the codes referenced, the CERM, the Useful Equations, my School of PE notes, HP 33s, HP 35s and a couple other things I thought might be handy but didn't use (Geick engineering formulas and Schaums outline for hydraulics).
The biggest time SAVER was having the useful equations ore programmed. I didn't use it as much as I'd hoped, but for instance an open channel flow problem that might take 3-5 minutes by hand with a calculator takes about 30 seconds to find the equation and punch in the inputs. I set up a tower crane problem based on the school of PE example and NCEES sample one as well, and that is another that took about 5-10 minutes by hand but about 30 seconds with my saved equation.
My position going in was foremost familiarity with the CERM, useful equations, and NCEES sample problems. Codes were only for reference if I got into a total pinch or there was a problem specifically looking for a code citation. My test taking philosophy was to go through and do all the problems I knew directly or could easily solve with the CERM or useful equations, then another pass with the school of PE notes, and a final pass for any code lookups or anything else since I knew those would take he longest.
Exam day the morning session I was wrapped up in about 2 hours, spent an hour going back over every problem and reading for clarity (did units align or were you having to use context to halve/double a rate, etc), and finished the exam fully cited to CERM or another reference for my own verification about an hour early. The afternoon session I finished about an hour early but had a couple to go back over, finished all but one and checked all my other work, and spent the balance of the time working through the one problem I had trouble with (it required using a reference I brought but was wholly unfamiliar with).
Hope this helps. I'd recommend staying with construction since it sounds like you don't do water resources on a daily basis (BUT, if you haven't, get any other sample exams you're considering from NCEES and see how you fare - I went into the whole process thinking I'd take structural as that's what I had the most singular experience in, but fared better in the construction practice exam). Best of luck!
