I just don't get how people think easy runs are supposed to improve your 800. You need:
- aerobic work, but I don't follow the line that 90 min runs are needed. At your level you're as good doing cruise intervals - eg 6-8 x 1km at approx 3:30 pace on the 5' (and on a trail) - and keep all year round
- vVo2max stuff - eg 6-7 x 2 min @ 2km pace/2 min @ 60% of that pace (or 5 x 3/3) (winter)
- speed development yes, but do it properly - gym, sleds, real top speed and acceleration stuff, short (6 second) hills, medium (12-15 second) hills. That is off season, you can build to 80s, 100s, 120s, 150s etc, but 150-200s aren't really speed work, it's speed endurance assuming you can run fast enough.
- specific 800m work - do diagonals in winter (racing flats on fake grass soccer field is best), a great way to work at close to 800 pace, work on form, reps not too long, do it for 20 mins and build to 30
- them move to 300s, 400s and 500s at 800m race pace, 1.5-2km of volume
- and in season once a week work at 1500 pace, eg 5 x 600m
- also in season consider once a fortnight doing a specific 400m session to help you handle the first lap at 5-8 seconds off your 400m PB - eg 3 x 300 at 400 goal pace with 12-15 min recovery