When you go to spend money you need to look at what you have left in your budget and next do you have money in your bank account? You shouldn't ever look at your bank account and say "I have plenty of money to spend", when you are over in your budget. You will get yourself into a hole that you wish you would have never gotten yourself into.
Keep up a current check register. I know that everything is online now, but you still need to know what hasn't come through so you will know how much you actually have to spend in your account.
This might all be foreign to you but in the end it will bring you peace of mind and you will sleep better at night I promise!!!!!!