I was you a long time ago, I ran 35 as a 15 year old, 33:56 as a 16 year old and 32:42 as a 17 year old. Track times improved from 4:36 mile to 4:27. Biggest improvement came when getting mileage up to 60 per week, about an hour per day at my pace (didn't always run easy but never ran hard, did run fast when I felt good but it wasn't "hard") , lots of hills, some unstructured fartleks. Only ran 10K's between seasons or in the summer (we all did back then). Ran workouts during the season but none between seasons and none specific to 10k, no runs longer than 12. A 15 mile long run for someone running 60 miles a week is way too much (25% of weekly mileage). If you have to do workouts do the basic 6-10 x800, 6-8 x 1k, 4-6 x mile once a week but alternate one week track and 1 week road or XC course. Don't start at 5:30, that's your goal pace , start at your current pace. A 20 minute tempo is good too and 5:50 pace is fine to start with., if it's easy slightly increase the length. You want to learn to run fast and relaxed, all out intervals and tempos do more harm than good. Don't be a slave to the watch or Garmin, learn to run by feel. Race every few weeks at all distances. Also, strides a couple times a week from 80-150m are always a good idea for any runner training for any distance. Good luck, have fun.
I don't really see the benefit of a 3mi tempo at 5:50 personally. From my experience a longer run (say 6-8 miles) is going to provide the most benefit. You're more of a speed focused guy so these runs will be the most difficult but over time you should be able to do 8@5:50 as an "easy but not too easy" run and 6@5:30 for a more tempoish run.
You're not in that shape now but you can work up to it, for example doing 4-6 miles easy then 2 miles at tempo, then slowly making more of the run tempo instead of easy.
If you're looking for a tempo pace at different run lengths there is a table in Jack Daniel's 2nd edition that you can find online[/quote]
Thankyou mate, so I should be doing a long run and long tempo?[/quote]