Classic personal finance advice is to set up a direct deposit out of your account to another so that once your check lands money automatically goes to savings.
I don't know how it applies to the UK but the 50/30/20 rule for budgeting is a good handy one if you're terrible at budgeting. They usually recommend you do this for your post tax take home pay.
So you're standard expenses should never exceed 50% - thats your rent, mortgage, car payments, utilities, food shopping, phone etc.
30% is your fun money so thats drinking, eating out etc.
20% is savings.
Relatively decent method and I think the main idea is that it'll immediately flag if you're in a dangerous or unsustainable financial position. If you're fixed expenses are more than 50% of your take home pay you definitely have a problem and you'll have to see what you can cut.