Clutter is much more than the physical clutter most of us think of. As for the physical clutter, ask yourself the following three questions about each item in your home and life. If you can't answer yes to at least one, it's probably clutter!
1. Is it beautiful?
A stunning piece of artwork enriches your life because it brings joy each time you see it. A gorgeous vase full of fresh flowers reduces stress and energizes your spirit. But if you look around your space and see visual clutter and stuff that has no meaning to you, you feel stressed and overwhelmed. Only keep in your space that which has meaning and brings you joy.
2. Is it useful?
Worded another way... does it serve a specific purpose in your life? For example, you use your 12-cup coffee maker every day. You couldn't make it through the week without it. In this case, the coffee maker serves a specific purpose in your life. However, let's consider the tortilla maker stuffed in the back of your cabinet that you haven't used in over a year. Consider this... you've done without this appliance for over a year - so is it serving a specific purpose in your life? Is keeping this item worth the space it consumes? (Don't confuse this question with, "Will/Could it be useful someday?").
3. Is it loved?
The antique pocket watch from your grandfather is a precious reminder of him. Your favorite cashmere sweater makes you feel fabulous.
You'll find that as you inventory your possessions, you may be able to answer "yes" to two or even three of the questions above. Those are the things that are most valuable to you. Remember, the goal of decluttering is not to toss everything. It's simply to keep only things that you truly appreciate and actually use.
To stop clutter, prevent it from accumulating in the first place. Don't give clutter a chance to form. As you've probably experienced, once clutter occupies a space, it has a way of spreading like weeds.
Always remember to place your emphasis on quality (of life) over quantity. In other words, it's not important to have a lot of things, many of which you never use. It's more beneficial to have fewer things, all of which you use and/or enjoy.
Think before you buy. As a Professional Organizer, I believe over-buying is the crux of many of our clutter problems. Try to look beyond the initial "thrill of the purchase" and see what provides deeper moments of meaning. Before you buy, know the specific purpose and home for every item you purchase, and consider the time you'll spend maintaining the item after you bring it home (and the space it consumes) - cleaning, storing, and maintaining. If you must buy, establish a "new item in, old item out" system where some purging takes place before shopping. This is a habit that we adhere to in our home consistently, especially in our closets.