For one to save money they must know exactly where their money goes. Keeping all your receipts is an easy [and sure-fire way] to know what how you spent your money, what you spent it on, etc. At the end of the month take a look at your receipts examine them. Identify the things you could do without. Cut them out of your budget and keep that money in your wallet, bank account — wherever you please.
That's a good idea. I've been doing it for years. I also make a plan every month of how I will be spending on food, bills, entertainment, etc. I rarely overspend. Instead I often find myself saving a few dollars here and there, that end up in my piggy bank. I find that good organisation is everything when it comes to saving money.