* Kit: Bits of kit (other than shoes) are probably not going to make any positive difference if you go out and buy them. I would say however that I’m assuming that you have the right kit in the sense that what you wear does not make you either too hot or does not help keep you warm enough. If, for example, you are too hot you will run slower.
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.