Race tactics for all!
Never mind the PBs, races are all about competing! It's about seeing how high up you can finish and beating the competition.
Track races:
Many track races in championship events turn out to be very tactical. It usually is slow for the first 3/4 of the race then bursts into life with a wind up over a lap or two. In these races it is important to be very reactive and ready to go with any sudden moves made. The worst thing that can happen in these races is that your boxed in when someone makes a sudden kick and by the time you have got out to chase them down they would have built up a 20m lead!
The pace is hot from the gun judge your efforts even if it means your behind at the start as many people ahead of you will drop off from going out to hard! Although you don't want to be too far from the leaders at any one time it is important to try to keep something for the last 1/4 of the race
Cross country races:
There isn't usually a whole lot of tactics in cross country races although sometimes they come into play. It is important to get a good start so you don't have to struggle to pass loads of people on the course as the race progresses. Once you have established a decent starting position it is mainly about being relaxed and controlled especially for the first 1/4 of the race.
If your aim is to finish high up in the race you can't be too far away from the leaders at any one time because it's very hard to catch back up on a cross country course!
You also need to save something (not much but just enough) for the last 150-200m to avoid getting passed out by kickers or to gain an extra few places by overtaking people!
Road races:
Tactics are never really too relevant in road races unless you are expecting to win or place very highly. Usually the pace the leaders set out at will be too fast to compete with so the best way to finish as highly as possible is to run as fast as you can.
I would recommend in this case running the entire race at an even pace. It may feel easy at the start but you will undoubtedly feel the pain in the second half of the race where you will certainly be passing people out as you are maintaining your pace while they are slowing down!
For the longer distances such as half-marathons and marathons a negative split run will nearly work better. Starting off to fast in these races (even if you think it is a pace you can keep the whole way) is too risky for the amount you could slow down later in the race. Even if it is just 5 seconds per mile slower than you first intended you can always speed up if feeling good and catch that time back up!
Overview:
In my opinion races should always be done with the intent on finishing as highly as possible and not to worry about the time. Racing to compete will bring faster times regardless if you run them in the correct ways. I hope these suggestions on race tactics shall be anyway usefull in your upcoming races!