This past month, my little sister was complaining about her cell phone bill. She asked me to take a look to see how she could bring it down some. She knew she had went slightly over her minutes, so that was expected, but what she hadn't caught was a $29 charge for a download that wasn't hers. She called the company and they fixed it plus gave her a credit of $30 for finding a mistake! Wow!!! I also showed her where she had used directory assistance 4X and she could have saved the extra $6 by dialing 1-800-FREE-411. She's also going on a texting plan for $5 extra a month, but it will decrease her bill by $10, since her text usage charges were around $15 every month.
I always fine-tooth-comb our bills. Our cell phone bill is one that I often find mistakes on. Even though it may only seem like a few cents, some companies will offer an extra credit if you find a mistake that was theirs.
It's also a good idea to shop around for better deals with different companies. No, you don't have to switch to take advantage of promotions a company is running. But what you can do is call your current company and see if they will match the promotional offer for the same period of time to keep your business. I've done this with our cable and phone bills.
If your utilities have had an unusual spike lately, call customer service and have them check. My aunt's water bill doubled, but she had received a notice saying that the rate was increasing, so she didn't question it for several months. When she finally did call they figured out that she was paying her neighbor's bill, too. If it's a higher water bill, you may also want to look for leaky toilets or faucets. For a toilet, you can put a few drops of food coloring in the tank, and if the bowl water turns colors, there's a leak. It may not seem like much waste, but it does add up.