One thing I’ve learned over the years is not to have my savings account linked to my debit / ATM card. If I want to make an impulse purchase, I have to put some thought into it and move money either online or at the bank. This delay gives me time to talk myself out of wasting my savings on something I don’t really need.
An added benefit to keeping your accounts separate, is that if your debit card is stolen, the thief cannot access the money in your savings.