In base you need to spend at least one day a week, maybe 3 per fortnight, on speed development. You need a good coach to teach you this. This includes meaningful gym work, plyos like speed bounding, push/pull (sleds), short hills, acceleration work. Do this for 2-3 months.
You can then stretch this out to 200 training, like 15 second hills flat out, and 80s, 100s, 120s etc.
Then for 2 months leading in to main comp phase, do 400 specific workouts. One good one mentioned above is 3 x 300 full recovery. That is tough. Another is 5 x 200 at come home speed (2nd half of 400), on 2 min jog/walk back. Another is 2 x (4 x 60 + 200), with 30 secs between reps and full recovery between sets. The 60s are at 400 speed, and the 200 is all out after you've fried certain energy systems.
Personally, I think this should be incorporated into the training of anyone wanting to run fast at 800. You need speed. Rudy and Amos win the 800 because they are the fastest over 200-400. Coaching endurance is a lot easier than coaching speed. You need to speak to some sprint coaches and join their squad once or twice a week.