One little section at a time.
Start with junk mail, catalogs, magazines. Put them in the recycle bin and then take a look at what's on your surfaces. Clear off the tables, dust, and replace only the trinkets you absolutely love. Donate the others, or pack them up in a box. I hope that gives you a start Jennifer.
Get three boxes - one for keep, one for sell, and one for donate. That way, you are getting rid of 2/3 of the amount of stuff you don't use. If you haven't used it in the last 12 months, then put it in donate or sell boxes! You'll be amazed at how much better an area looks just by getting rid of stuff you don't use!