I was for several year a very average "joe runner"...
not really talented and picked-up running only in adult age.
Running for several years 10k in 36-37'.
I went down to 33' in 1 year, why?
- running religiously every day (maybe only 7/8km easy, but avoid missing days)
- running more: from 50/60km, I moved to 100/120km weekly
- 3 workouts weekly
1st: strides and faster workout to improve my leg turnover: the workout was not very demamdning in itself (not a VO2max workout, but more like fast intervals at brisk pace, without reaching fatigues state)
2nd: a solid tempo run/long intervals workout (reaching 10/15km of HM paced effort)
3rd: a long run, but with some variations and/or faster final
+ easy days, using HR monitor to keep HR under 70/75%HRmax
most of all, follow the well-known advice: do not borrow the workout from tomorrow's one... do not end up dead at the end of the workouts, must be a fatigue that you can recover in 24/48 hrs.
I did my 10k and 5k PB while training for a marathon...
avoid too many interval training workouts: 4 o 5 weeks with 1 specific Interval training workouts are more than enough to reach a peak. Doing VO2max intervals all year long will only make you tired.