I would not "push the pace" on regular daily general aerobic runs. Don't worry if the pace is 9 minutes a mile or even slower. Run relaxed and easy. If you don't run easy enough your body won't overcompensate and improve from the work you've done on hard days. You may need 2 easy mileage days between hard days. Do your long run easy too. Hard days could be 2 or 3 per week: short intervals or hill reps (200s etc), long intervals and a tempo run or short race. Run consistent mileage, 50 a week should be enough to improve to 18m for 5k.