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 : https://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.
Tip 1/50. *** Don’t train AT ALL!! A 3 day abstention (taper) should suffice for many levels of runner i.e. Wed/Thur/Fri – do nothing. More serious runners will benefit from activity during a taper, even the day before a race (see later).