Keep an eye on all Direct Debits/Standing Orders.
Try not to use credit card (if I have to then I keep the receipt and try to put money aside to pay for it out of weekly cash).
Try to stick to taking cash out once a week - a little more than you think you'll need (so if you think £100 will pay for travel, shopping, odd cup of tea, etc, budget for £120) then you won't be tempted to 'switch' shopping (and add some extras of you only need a pint of milk). If you have money over at the end of the week, put it aside as there will be some weeks when you need it!
Be realistic calculating bills - remember that gas/electricity/car servicing/insurance...all go up every year!
Be an insurance/mortgage tart. When the renewal notice comes in, look around for a better price. Sometimes you will see offers on insurance that offer to match any other like-for-like offer AND give you some money. Pay bills like this in istallment ONLY if it is interest and fee-free (money may as well be in your account).
Get a penny jar! You would be amazed how 20 and 50ps add up. Even try a £1 for Christmas.
Put a little something aside each week/month for the kids birthdays and holidays. Then feel extra smug when you pay for the birthday party without going into the red.
Shop around for groceries (if you have time). Some of the 'essentials' and other store brand stuff is really quite good.
Look carefully at your bank statements. Highlight the 'naughty' stuff and see how it all adds up (£10, £20 out of the bank a couple of times a month, 'switching' groceries... all add up).
You don't have to like like a monk - see what you can realistically do without and what you can't - ie if you work all the hours and have the luxury of a cleaner 3 hours a week, well, if that makes life better, then keep the cleaner. Maybe you can save the cash elsewhere (maybe a gym membership that you never ever use?).
Keep some money aside each month for 'mad money' - cinema, pizza... you need to once in a while!
E-bay the stuff you don't need/use. Good quality used kids stuff sells well.
That's it for now...