Here's 2 different approaches neither of which "work for the masses". At first, you might need to send yourself a reminder to do it everyday for the first week or so (google calendar). Once you are well into it, you may skip a day or 2:
1. Get a receipt for everything you buy, whether cash or not. At the end of the day, enter the item on a spreadsheet or a budgeting program. Look at your budget and what you are spending, whether it's gum at the gas station, a new tv on Amazon, etc.
And/or
2. Set up bill pay for your credit card (stick to the one that pays the most rewards and freeze the others to only be used a few times per year). Each time you make a purchase, zero the card out via billpay. This keeps your perspective and no surprises on the statement due date. Your checking balance is a "plumb line" of sorts (as if paying with cash or a debit card). As for the float you surrender: It's really not worth anything significant. It kind of makes your credit card a debit card. It requires discipline.