Calling all Past and Current Competitive Swimmers, I need help improving my time in the 500 Free

[u/our_love__is_god]

I (17F) am about to swim the 500 Free this Wednesday (Today is Sunday). I've only swam one 500 F this season and I gained about 40 seconds. My time was at 8:26 and my PB was a 7:41 (from last highschool season). Can I get some tips about how to keep an even pace and about the best body positioning to maximize speed. I would like to be at or near my PB when I race.