Running much faster in intervals than the target paces is how to achieve the target pace when running the race. Too many try to only run a little faster than the target pace during their interval workouts.
I offer below a baseline. It is a 4-week cycle, so just repeat 3 times. You can gauge your improvement over the last cycle.
This is good for racing fast at 800m - 10k.
I raced 800m (and miles) in HS and college. I ran CC in HS, and in my late 20s I raced on the road.
WORKOUTS (4 week cycle)
Note: Day 4 and Day 6 change for each week.
Day 1. One aerobic distance run per week: in HS, we would do 1 hour and cover about 9 miles (6:40 pace).
1a. So...run for 1 hour, once a week. It is meant to be aerobic, which means you are not short of breath. We did this on Sundays. (my HS coach trained for CC under Dellinger and Bowerman during his graduate studies at Oregon).
1b.. In college, we ran 10 miles in 58-60 minutes.
Day 2. Lydiard fartlek: 5-7 miles, building up to a fast, sustained pace, then slowing down. 3-4 such builds in the workout. We would build for about 800m and sustain for approx 400m.
3. Homer fartlek: 4-6 miles, running 6:30 - 7 minute pace (or whatever suits you), then stopping for several fast sprints with very short recovery (50s or 100s). Repeat the sprint phase 2-3 times during the fartlek.
Day 4. Speed that will be sustained over distance:
4a. Power run once every 4 weeks: 4-5 miles (can eventually increase to 6-8 miles) almost as fast as you can run that distance in a race.
4b. Next week: run ladders (600m, 400m, 200m) or (500m, 300m, 100m). Run 2 repeats of the ladders, with about five minutes between intervals, and 10 minutes between sets. In other words, 3 sets of ladders, and it can be 3 of the same, or mix up the two. Run at expected mile pace for the 600, 400m, 200m; run at expected 800m pace (sub-2) for the 500m, 300m, 100m.
4c. Third week: cut down the rest in (4b) to 2 minutes between intervals, and 5 minutes between sets.
4d. Fourth week: run 3200m, such that the first 800m is at your expected mile pace, and the second 800m at two mile pace, and the third 800m is at your expected 5K pace, and the last 800m is at the expected 10K pace. Float for 15 minutes after the 3200m, then run 4 x 300m with a 100m jog, with the first one at expected 800m pace, then each one faster than the previous one.
Day 5. Weights
5a/ If you can, also do water running for 15 minutes: 5 minutes at 2-mile pace, 3 minutes slower, 3 minutes at mile pace, 1 minute slower, 1 minute at half-mile pace, and 2 minutes slower.
5b. Water running is great for aerobic and anaerobic, even if injured.
Day 6. Form work (Run with power)
6a. First week: rest..
6b. Second week: Warm up 2-3 miles, stretch, then 4-6 x 200m strides at 85% of full sprint speed, and then cool down. I prefer 200m straightaways, and the 200s don't have to be on a track.
6b1: Running is jumping (leaping), so work on taking the longest strides possible without slowing down hips, and without shortening the angular rotation of the hips during the stride.
6b2: Churning is when runners shorten the hip's angular rotation to get their feet on the ground more frequently, which is inefficient.
6b3: "Run-walking" refers to runners that rely on momentum and the rolling on the foot as the body's weight passes over the foot so as to appear to be taking small leaps, and this is very common among most distance runners (but not common among elite racers).
6c. Third week: Repeat 6b:
6d. Fourth week: rest
Day 7. Rest or race or time trial, depending on the weather and time of the year.
If you want, add in 2-3 miles per morning, for 3-5 mornings, all at a steady pace. When you race faster, the pace of the morning runs will likely increase over the months.