That I could run the full distance and I didn't need to stop and walk 100yds at mile 24 just because my body was knackered and my mind was telling me to quit
That I should have faith and belief in myself after 5 months of training on hills, in weather, around family/work/life and that if I can do that, a marathon's a piece of piss (relatively speaking)
That listening to my body is definitely the best way to look after myself in a marathon.
What little gem would I impart?
If you know you hate Lucozade sport drink, don't pick it up at mile 12 and make yourself ill up to mile 19 - wait until the next water station
Post marathon nookie is the best and most efficient way to minimise doms. Just find a room first please.