There are 3 main categories for how to corral paperwork: not letting it into the house, eliminating and simplifying what does make it in, and finally figuring out a system for the paperwork that you need to hang onto.
1) Don't let it in.
Can you reduce some of the paperwork before it even gets into the house? Try paying bills and viewing bank statement online instead of getting statements and bills in the mail. If you buy something online, instead of printing the receipt, print to pdf and save the receipt in a receipts file on your computer instead. Set up and use your landing strip to sort mail as soon as it comes in, toss that junk mail right into the recycling bin before it becomes a pile to deal with later. Better yet, cancel the catalogs you don't want to receive and take yourself off the junk mail lists
2)Eliminate and Simplify. AKA The Internet is Your Friend.
You may need to tackle the paperwork that's already in your filing cabinets before you even have the space or new stuff. Consider investing in something like the fujitsu scansnap to seriously reduce the paperwork overwhelming your cabinets, your desk, or the floor. You can scan old receipts and documents that you need to keep but don't need to have the original. You'll still have to organize the files on your computer, but it isn't so physically overwhelming.
Make sure that you aren't hanging onto paperwork that you don't need anymore. Bank and credit card statements can be accessed online so you don't have to hold on to the papers. Make sure to shred these documents. One of the biggest differences for us was when we ditched all of our old cell phone bills, it must have freed up 6 inches in the filing cabinet. Do you have old manuals for gadgets you don't even own? Can you access the manual online if you still own the fridge, dvd player, cell phone, etc? Get rid of those.
We keep this organizer on the desk so that we can immediately file receipts, blog ideas, and bills to pay. This eliminates the piles. We also keep a file on different projects we're working on or anything that we need to access frequently. We have a larger plastic banker's box that we keep in the closet for everything else. (At our old job, we would get a new one for each year so that it was already ready to get archived in storage as soon as the year was over and we didn't have to have a big ugly filing cabinet).
It's important to have a system so pick a day for paying your bills each month and then stick to it. We recommend working in an extra 15 minutes to file each time you sit to pay bills, you'd be surprised how much you can file in 15 minutes. This builds in an automatic slot for keeping on top of paper clutter once you've gotten it under control.
So, our actual system for filing: Alphabetical. It's simple and it works. From Car to Medical to Receipts to Tax Returns we just put it in order. Within each file, we go from front to back, oldest to most recent, so we always know that the latest bill is at the back of the folder. It's foolproof.You can make it more fun with stylish file folders.
As with all decluttering, the important thing to remember is that it took a while for things to get out of control, so trying to tackle it all at once will probably make you feel like you're going crazy. Start with babysteps and be consistent and you'll be surprised at how much progress you make.