I make a menu for the week and then put together the grocery list with only the ingredients I need to make the meals I had planned. My husband goes to the grocery store and will buy ONLY what is on the list. Nothing extra whatsoever. If it isn't written on the list, he won't buy it. It really helps when you only go once a week as those side trips every other day add up.
I also have been considering trading in my car and leasing. The savings is amazing! My husband is driving a Honda Accord for less than $200 a month and he can trade it in next year and get another one. We bought my Odyssey and I really think we can have lower monthly payments if we leased. He is looking forward to having a car that is paid off, but every time we pay one off, we take it and trade it in for a new one so what is the point?
Coupons...I have heard that you can really lower the cost of things by using them. I actually managed to get a few things for free at the grocery as the coupon was for more than the price of the item! I don't have that much patience for them but if you do, they can be worth it!
I am sure there are lots of other tips but the best one for us is the grocery list thing. We rarely go out to dinner and it saves us tons.