Take a break if you have been training hard for 4-6 months straight

If you have not run in over a month gradually build up your mileage

If you are sick, do not run

If you are injured not run

Vary your runs in terms of distance, hills and pace

Be consistent in your training

Each week run 3-6 days per week depending on your fitness

You can do core exercises 2-5 times per week (Very Important)

Do circuit training for general strength work

Have fun