I double layer the kids beds so when they wet the bed at night, I whip the first layer off with minimal hassle (so it would be mattress, waterproof sheet, sheet, waterproof sheet, sheet).
Give warnings - I get less grief if I say to ds "after X, I will brush your teeth".
Give them responsibility for things even if it is more hassle. Eg let the kids clear their plates, let them have a go at helping with cooking, give them cleaning or gardening jobs. The sense of pride they get for helping (and not in return for money) is palpable! Ds was so proud he helped dh load the car up for the rubbish dump the other day, he came to tell me and was glowing.