If you're like most people and don't look forward to organizing projects (ok, you dread having to give up your time to do this), start with something small.
Pick an area that you use everyday, whether it's a drawer, a shelf, or a cupboard. When you don't have a lot of time to devote to organizing and tidying, this is an easy way to get started and see an immediate difference.
I worked with a friend recently who wanted help taming the storage area outside of her kitchen. This was a multipurpose area but items still felt scattered - she had all kinds of cookbooks, tupperware, and canning supplies spread throughout the kitchen and this little station.
We spent about a half hour total to whip this station into shape. She donated about half the cookbooks, purged mismatched tupperware items, consolidated the canning items to a separate cupboard, and have two shelves open up for snack storage. What a difference this makes in a smaller living space and now she can access everything a little bit easier!