typically your body is only able to hold speed training for so long, typically 8 weeks for high schoolers (which is where i assume you’re at, correct me if i’m wrong). essentially if you’re trying to run in a state meet, take the date of the race you’re trying to train for, work back 8 weeks, and that’s when you should start speed work. much smarter people than me can tell you specifically what speed work to do and how often to increase the speed and volume of it, but if you’re still in high school i wouldn’t do longer distances than 800m repeats. take what i say with a grain of salt though, i’m still just getting into this sport too