I keep one of those stacked file bins on my desk. Top basket for IN, next for HOLD, and bottom one for FILE. A key thing in keeping things uncluttered is to do away with what you don't need ASAP. Don't get distracted with things that come up suddenly … stay on track to get done what you wanted to do when you sat down. Computers have a way of wrecking your entire day if you let it take priority over your own priorities.
Have a good filing system/cabinet and schedule to go through it every 6 months to clear out what is no longer needed. I've seen people get another and another filing cabinet because they keep everything that they already have. I can assure you, most of what's been filed for years is no longer wanted.
We have a business besides personal filing. I'm able to keep the business files at one drawer by going through it regularly to clear out what is not needed. At the end of the year, most of it goes into the tax box anyway. Then I use two drawers for home filing which goes back to 1977 in some cases, but the key is that it's cleared out twice a year so that I am able to only have two drawers of personal files. Not only do I love the simplicity of not adding filing cabinets (they're not really pretty are they?), but it makes it easier to file what I do want to find.
Clutter only makes you spend more money since you get to where you have so much stuff, there's no place for the stuff, and so you go and buy something that you already have, but don't know where it is.
Sorting things into categories is what makes clutter-free abodes for all your household stuff. : -)