Decluttering is essential to keeping your head above water. Excess stuff can really pull you under. Be ruthless. If it isn't something you love or something you use, get rid of it!! Don't allow your things to control you. You are in control of your stuff.
Unfortunately, for most of us clutter is a constant battle. Stuff is always coming into your house. As an item comes in, remember the rule. If you don't love it or need it, then pass it on to someone else. Don't fall into the trap of buying something just because it's a great deal. Don't take other people's cast offs because you feel bad telling them no. Remember ... be ruthless!!
So, how do you declutter? You go through each room and get rid of everything that you don't use or love. If someone else can use it, then donate it or try to sell it. If you're going to sell it make sure you put a time limit on how long you will hang on to it. If you know realistically you will never get around to selling it, then just give it away. If someone else can't use an item, then throw it in the trash. If you've let things overtake you, you may need to rent a dumpster for this step.
Fo those special mementos (kids papers, artwork, etc.) try to limit yourself to one rubbermaid container. With the advent of the digital age, you can just take a picture of so many things and not have to keep the original. This works great for kids' artwork. You can even make a coffee table book out of all their best work! If you want to keep some mementos from you children's childhood, keep one or two items. You don't need to keep every cute outfit they ever wore. Chances are they aren't going to be happy about inheriting it all one day. One baby dress is a cute memento. A whole wardrobe is overkill.
If you are unsure about an item, put it in a sealed box and stick it in the garage or basement. In 6 months or a year, if you haven't missed it then you don't need it! I've only have a handful of things over the years that I've regretted getting rid of. Usually they were inexpensive items that I could have easily gone out and replaced, but I didn't miss them enough to do that.
Getting rid of the clutter lightens your load, enabling you to keep your head above water.