*** Eat a light, simple breakfast as long before the race as you can. You EASILY have enough energy for a 5k already in your body. Big breakfast = discomfort + weight + blood moving to your digestive tract rather than your muscles. Temper this with knowing what works for you e.g I NEED something but can usefully eat a banana or maybe a Lucozade Sport (the Elite ones are good).
All the suggestions are starred:
*** 3 stars. IMHO it will work
** 2 stars. It might work
* 1 star. Can’t hurt
X 1 cross. It CAN hurt if done wrong.
All 50 tips are shown here as a series of posts : http://the5krunner.com/tag/how-to-get-a-5k-pb/ or on twitter using #howtogeta5kpb. They are all SHORT-TERM tips that will work in the next week or so with varying degrees of success.