Some thoughts from a nobody -
As a developing HS 400/800 runner, you will need a mix of workouts.
But first, consider your easy aerobic days. You will need 3-4 easy days with easy runs 20-40 minutes (depending on your fitness. For best results, try AM and PM easy runs. Two daily runs of 20-30 min will give you more benefit than 1 run of 30-40 min.)
For workouts, you will need top speed sessions like 5 x 60m and 4 x 150m. You will need aerobic workouts too, so when the distance guys are doing 6 x 800 maybe you can do 4 x 800, or if they are doing 12 x 400 maybe you can do 8 x 400. And you will need transitional workouts that benefit both your 400 and your 800, such as 100-200-300-400-300-200-100 ladder and 6 x 200m.
For races, early to mid season inude a mix of sprints and distance, don't just run 400 & 800 all the time. Sometimes hop in on a 4 x 100 or 4 x 200. Sometimes run the mile/1600/1500. As you get mid to late season, focus more on 400 & 800. End of season, probably pick one for peaking.
Hope this help :)