*** Drink as little as you can on race day (assuming an early race). You are PROPERLY hydrated from yesterday and previously right? 500ml tops if you need something. Although if you feel thirsty you should DEFINITELY have something. To be clear you must be sufficiently hydrated but you do not want litres of excess liquid in your stomach.
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.