Learn to differentiate between necessities and clutter. Take stock of everything in your house. Are you keeping things you haven't used in years? Are you keeping things that you can't even remember what they are anymore, such as mechanical parts? Do you have lots of unused items that are cheap and easily accumulated, like rubber bands, wire hangers or plastic bags? These sorts of items are clutter.
Pare down your nostalgic possessions. If you're keeping piles of old magazines, tear out your favorite articles from each one, put them in a scrapbook and send the rest to the recycling bin. If you have boxes of essays and work from your school days, pick out your best work and throw the rest away. If you still have a closet full of baby toys and your child's in high school, put aside the toys connected to your favorite memories and send the rest to charity.
Transform clutter into memories. Take digital photos of clutter with sentimental value and store it on a single CD. Buy a notebook and write descriptions of items that need to be thrown out.
Reserve a single cardboard box as the sole storage space for things you don't use but think you might need in the future, such as decorations, tools or spare parts. Once this box is full, force yourself to throw something in it away before you add anything else to it.
Enlist friends and family members to help you remove the clutter. Make a fun day out of it. Turn on some music, order a pizza and reminisce about the items you are discarding. The extra hands will do more than cut down your workload. They also bring an impartial voice that can help you decide to throw things out you might otherwise keep.
Make a habit of removing clutter. Set aside a single day every year -- or more often if things accumulate quickly -- to go through and whittle your possessions.