Buy Yourself a Gift Card - One way I budget for an extra, like Starbucks, is to buy myself a gift card and use that until it's gone. If I budget myself $20 for the month to spend on Starbucks I can use it, but not go crazy. If you're going and paying with cash every time the actual cost adds up without you even realizing it.
Order Off the Kid's Menu - I never eat all my food, it's so wasteful. Well, now I try to order off the kid's menu, it's smaller portions and usually cheaper. Pei Wei is a great example, I will never eat all of a reguler entree order but I can order off the kid's menu and it's the perfect amount of food. The selections are usually limited but it's worth to me. Subway has a kid's sandwich it's small but I will get that, it's less than $3, and then have a veggie (canned green beans, carrots, etc.) with it and it's more than enough food. Also, if you're at a restaurant and feel weird ordering off the kid's menu (I would) ask your waiter if they will do a half order, most places will, they just don't advertise it on their menu. It's not half the price, but their is usually some taken off the price.
Carry Cash - Budget yourself for the week and get cash instead of using your debit card. Mindless spending is so dangerous. I try to take $20 out at the beginning of the week and use it through out the week for my breakfast and lunches.