If you can go through each room in your home with this mind set it should make the process of picking a choosing a bit easier. Something else you can do if you are really attached to things is bring in an other person who can help you identify your needs. This can be extremely helpful since they won't have the sentimental attachment to your items or furniture. Then after your needs are met it is totally up to you to decide what you are willing to let go of.
Some times my motivation to let of things that I'm not actively using is finding someone who I know will appreciate it. It kind of puts my mind at ease. I really enjoy vintage and antique items. I also highly respect their craftsmanship. It is so much harder to get rid of those things even if they are not functional. So I decided I wouldn't get rid of them, but instead I choose to find them new homes. Then everyone is happy, right?