Once you go through your possessions and figure out what isn't useful in your life anymore, once you have sorted the keepers from the giveaways, once you have made the decision to clear out the clutter and make more room for the good things in your life - What do you do with it all???? A few suggestions -
Throw it out. Be ruthless. There is always plenty more of where that came from.
Give it away. Ask your friends and relatives if they can use any of your castoffs.
Donate it to charity. Churches and social clubs are always looking for items to sell to raise funds. They will do all the work and you may get a tax receipt.
Find out if there is a resale store or a consignment store in your town and make some extra cash.
Join Freecycle at www.groups.yahoo.com or visit the main site at www.freecycle.org It's fun and easy to start a new group if there isn't one close to you. Instead of throwing something out - just post what you have and people that can use it will come and take it off your hands.
Hold a garage sale. Price each item reasonably and remember that you don't want it any more. Pick a date now and commit to it. Pack everything into boxes after they are priced and store them in one place until G-Day.
Sell it on Ebay. It's fun and easy. Just set up an account and make a little extra money from your efforts.