I need to get faster at getting things wrong.
Ding ding ding! You win a prize. I don't have an actual prize for you, of course. So you win the pride of knowing that you're right.
Yes! So much of the GMAT is actually about this right here: acknowledging what you do NOT know or what will just take too long and letting it go.
In terms of content area, I think geometry is my biggest weakness. The average difficulty of correct answers is 610, my lowest in quant, but I am getting those questions right fairly quickly; only 1:33 minutes spent on each question.
How many are you getting right vs. wrong? Are you actually missing lower-level ones? It's possible that you just happened to get an easier mix of a certain category / type on one test. Taken to an extreme, you could get 100% correct but still have the avg difficulty be lower - but that doesn't mean that you're bad at geo, just that you didn't get offered harder ones!
I don’t think I’m in a position to place items in buckets yet since I feel like I need to improve on almost everything in order to reach my target score. Do you think that is fair to do, or do you think I am taking on too much and should bucket regardless?
Bucket. Everyone feels like they could improve on everything. Sure. The point of bucketing is to
prioritize, because you can't do everything at once. And you don't really know what you need to get to your target score because you aren't there yet. Focusing on the easiest-to-improve things first allows you to move ahead incrementally until one day you realize, hey, I'm where I wanted to be, and I never did have to bother diving deeply into XYZ category that I hate. Yay!
So, yes, go back and bucket. Factor your gut feel into the hard data. For which types of questions / content areas do you feel, "Oh, I can totally learn how to do that!' vs. "Ugh. That's really annoying." Bucket accordingly.
Re: timing on verbal, try this when going through answers:
1st pass through answers: place answers into 1 of 2 categories, definitely wrong or maybe (which is anything that is not definitely wrong). DO NOT spend any time deciding whether something is
right at this stage.
2nd pass through: look only at the remaining "maybe" answers, compare, choose one.
When you are down to two answers on verbal, look at each answer ONCE more, then pick one and move on. No agonizing back and forth! You either have a hunch (in which case you might as well pick it now, because you'll have the same hunch 30 or 60 seconds from now) or you don't have a hunch (in which case you might as well just pick one now and move on, because you still won't have a hunch after 4 more comparisons of the answers).
That will also save you mental energy, which will help big time as you're getting towards the end of the section and just want this test to be over already!
So I plan on doing end-of-chapter foundations of math problems. Should I be timing myself while doing these?
Nope. You only need to time yourself on GMAT-format problems, where the goal is to learn how to think your way through / make the decisions as you'd want to make them during the test (when the clock is ticking). When you're doing work that is more skill-building or drill work, take whatever time you need to really learn / solidify the material. (Though do watch out for excessive double-checking of your answers or whatever, as those tendencies can bleed into your later GMAT-format problme practice.)
In general, I think you've got a good handle on what you need to do (but fill those buckets!). Let me know how the PEA goes. Good luck!