I got a 30 in the QR section, this is my study advice.
Other than having taken math courses beyond what was required (up through the second year of calculus), I took 17 full practice tests and came up with a good strategy for it based on DAT bootcamp, crack the dat, and other practice tests. Take as many as you can after you've read a good book to prepare. The Kaplan book is really good for a lot of it. I would take a full four-section test in the morning, then review it including reworking all the missed problems in the evening, and repeat the next day. I set a goal to put in 250 hours of studying for the DAT before I took it and hit about 200 hours in reality.
I recommend simply looking at a problem and if you don't know what the steps are going to be to figure it out within like 10 seconds (not to have the answer within 10 seconds, just the plan of attack), mark any answer, skip it and come back to it later. If you do know how to do it, then go ahead and tackle the problem. You should only get like 45 seconds on average, per problem to finish within the time limit.
Make sure you know what kind of questions to expect, and know how to do them. For example, if you know you're no good at trig, learn the basics you're shaky on in trig so you can do better at trig in a practice test. Use practice test problems to learn from. I suspect that unfamiliar math ideas can overwhelm some people. I think I memorized less than ten math equations for the QR section. The key is full practice tests, preferably on a computer including all science, PAT, reading, and math, so you are used to having endurance and timing, and knowing how you handle the test.
After each practice test review all the missed problems for each section, including the QR section. When you review missed QR problems, make sure you can work them and get the right answer, even if it takes you ten minutes to figure out one problem. Sometimes it may just be a really hard math problem. If it takes longer than ten minutes to solve while reviewing it in practice, maybe skip it after a good faith effort and save your brain or try to come up with a smart way to guess.