Definitely spend a fortnight - or month if you can - writing down everything you spend, be it cash or card, including the "little things".
Then you will have a clearer message about where your money is going.
If you haven't already, then spend one evening or weekend afternoon checking you have the best deals on all your phone, internet, insurances, utilities, etc - that can add up to £hundreds if you don't change each year.
Check your bank account - are you still paying for anything you don't really use ? - gym membership or a magazine subscription?
Set up a standing order to take £X out of your account when you get paid each month.... don't wait until the end to scrape things into savings, but save it from day one, and then, if you haven't got cash for it at the end of the month, you will go without it.
Have a serious look at your supermarket spend - I'm staggered what some people on here spend every week, when they could (if they wanted / needed to) only spend 1/2 of what they do.
the other thing is to think about how you can increase your income - maybe sell stuff, or are you able to do another job - bar work one evening a week (means you earn, as well as not spending that night - can be quite sociable in some bars or social clubs or sports clubs), or maybe register as a babysitter - when you can often get on with something else or just relax for 4 hours when dc are asleep, or some kind of home working (don't know what your skills are in)