If you are having a hard time being motivated, invite someone over. It will motivate you to clean your house so it will be clean when they come. I had a friend who would invite someone over each week because she hated to clean her house. She knew that if she had people over that it would help her to clean before they came. Nothing like external motivation!
On another note, inviting someone over to help you go through things is also a good idea to stay motivated and get the job done. It is nice to have another opinion or have someone who sees things in a different perspective.