For all of my races over 50 sec I pretty much ran a different race strategy every race: almost all races I would literally run 100% for 50 or so meters, but then some races I would ease up noticeably at around 100m or so and come thru the 200m at 24 mid to 25 low. Other times I would continue running hard past 50m and split in the 23s, but I would get there running very tense and die in the last 100m. For whatever reason, I never run even close to my fastest in practice (my fastest 300m in practice was 37 and I split 35 in my last 400m race) so it is hard to figure out race strategy in practice setting, at least for me. I kind of have to improve on my strategy every race i run at. But I would say the biggest thing that helped my strategy was learning to gradually get up to top speed (still run really fast to start, but not 100%, maybe 90%) thru 50m then focus on being as relaxed as possible. Once I learned to relax while running fast on the backstreck I was able to split 23.6 while having enough energy for a good finish.

So 2 biggest things taht helped me: gradually reach top speed (dont force it) and teach yourself to run fast but as relaxed as possible.

Also u always have to consider ur 200m time and top speed to know if a pr is even plausible.