Note: For the sake of simplicity, we're going to talk about getting bad reception in your home as an example, but these tips can work just about anywhere, like your office.
If you have a little bit of reception to work with — say, one bar, or salvageable service in certain places in your house, there are a few things you can do.
Find the areas in which you get service: If you're lucky, there may be a few spots (like by windows, doors, or away from big appliances like TVs and microwaves) where you get service. The quickest and easiest solution is to just make sure you don't venture out of these areas when you're talking. Make a mental (or physical) map of where your phone works and where it doesn't. Obviously, this isn't the most ideal, but it'll work in a pinch.
Use a Bluetooth headset: If there's an area of your house in which you get good reception, a quick and easy solution (that we've mentioned once before) is to pick up a Bluetooth headset, leave your phone in a good reception area, and just talk via Bluetooth. The range isn't incredible (so, if you have a big house, you'll need a few designated "good reception" areas), but it'll let you move around a little more while still getting enough reception to talk.
Try another phone: Again, it isn't ideal, but if you found that part of the problem is your phone, using a different one might help you out. In fact, you'll probably get better reception if you use one of those old phones you have lying around in the basement. Old phones often get much better reception, usually due to the giant antennas they have sticking out of them. If you're a smartphone fanatic, you won't like this option, but you can at least use them inside and swap their SIM card back into a new phone when they leave the bad-reception building.
Install a repeater: Sadly the most reliable non-VoIP option is also the most expensive. There are a number of pretty good cellular repeaters out there, that when installed, can spread some much better service across a room or two. Unfortunately, they cost about two or three hundred dollars, so unless you're hell bent on avoiding using your computer to make phone calls, you'll have to plop down some cash if you want maximum range and reliability.
Having bad mobile phone reception is annoying, but it doesn't have to make your life more difficult. Got any of your own tips for surviving bad reception? Share them with us in the comments.