To this day the most impressive and ingenious top tip I've ever encountered, was bending a wire coat hangar into a hook which fits around the shower pipes at Raleigh. It would hold the on button down and bypass the self cancelling system allowing you to have a nice long shower instead of a series of 4 second ones.
Top tips for the field?
Buy a jetboil, take loads of spare socks gash bags and bungees whatever you're doing, buy some dentist's tools for cleaning your rifle, Haribo aka Moralibo is all you need to power you around a CFT, girl's makeup removal wipes are the shizz for getting rid of cam cream, baby wipes can be used in lieu of a shower, the issue rollmat is perfectly adequate, don't bother with an expensive inflatable jobby, Rambo knives are for dicks, get a Leatherman.
When it comes to your Bergen, seperate all your gear into different coloured waterproof canoe sacks, one for your bivvy kit, one for your clothes, one for scran etc. Then put them all inside one big fat canoe sack which is lining your bergen. Makes shit easier to find in a hurry or at night, much easier to take three or four bags out than turn the ****er upside down looking for stuff. Also keeps everything dry if you end up taking a dip and it will make your Bergen surprisingly buoyant. If you need to cross some water it's always nice to have a float.
Put some scrim around your helmet and hold it on with a rim made out of the top of an old NBC boot. Remember Allyness saves lives.
Finally and most important of all, laminate your porn. Always laminate your porn.