The most common advice given to new runners by the grizzled veterans is "run more, run slower". Whilst this is invaluable it is the next step in the progression that I think there are benefits available. Once you're running more and slower, then go run some intervals.
There is nothing quite like a well run interval session. Whilst a race has it's own feel and experience you always need to keep a little in check for that kick or to cover a move by another athlete with a constantly "forward" goal. An interval session can be relentless in it's intensity. Often covering 8 or 10,000 metres of running at 5,000 metre pace with relatively short recoveries. Unfortunately to many athletes these intervals often become races in themselves. Whether this takes the form of them racing their training partners or just trying to run each rep or the whole session faster than they've ever done before.
When you see people straining flat out and watching their form totally disintegrate you have to ask "how much is this helping"? How often in races do we see someone in this kind of distress (Neilson Hall and Tom Cornthwaite excepted!) and being able to race succesfully? They're taking advantage of being able to generate a level of lactic acid in their body in order to finish reps quickly and use the breaks to let the level go down. Whilst there's certainly room in training for developing lactic tolerance it shouldn't be in long reps in which the primary aim is aerobic development.
Far better instead to take just one second, maybe two per lap which is really not a great deal and all of a sudden instead of straining and overstriding you're running at a relaxed powerful cadence which you can keep up for a entire race. Whilst there is a point available in that you should train at your current 5k pace people train at their "5k pace" were they in a race and fully tapered whilst in the middle of a training week having done a session two days before hand and a large number of miles, that second a lap is probably getting you closer to your actual 5k pace on that day.
Since becoming aware of this and trying to take my ego out of the equation interval sessions are more consistent, relaxed and I can see the effects in my racing.
Train don't strain.
Racing at the South of England XC Championships in an absolute mud-bath. I took 94th place in my senior debut which was a slightly disspapointing run but a very high quality field. Whilsta dissappointing run I beat a fair few runners I had never beaten before and it's a mark of the progress I've made in the last few months that this was a "bad" run for me. 3 months ago I would likely have been delighted!
Just behind me is Dan Thompson of Hillingdon AC who I actually got narrowly outsprinted by in one of my first ever XC races in the Met League U17s. I misjudged the finish, kicked clear and then realised I still had 300m to go!