The first step to any project is clearly identifying the scope of the project. Specifying what your aims are as a closed project will help you to know when it is complete. However, you don’t need to drill down into the details as you’re outlining your project. 
“Getting organized” is not specific enough. Equally, a list a mile long with specific instructions such as “Create 43 hanging folders, each labelled with 3.5 inch tabs with 20 point Arial font with the following labels… and filing all the loose paperwork into those folders, being sure to purge any utility bills older than…etc” is probably too much detail at the beginning of a project. 
thought bubble
Here’s how to identify the scope of a project. 
Choose an area to organize. It can be as small as a drawer in a bed side table, or a shelf in a closet. It could be as big as a whole room. (Again, “organize the whole house and the garage” is a bit too broad). 
Imagine how you want the space to be at the end of your project, and make that your goal. You might want to specify that all horizontal surfaces are clear or with a certain number of decorative items remaining, or perhaps that all like objects are together, or that you only want one of each of the types of objects in the space. However you choose to state it, someone else should be able to come into the space and say, “Yes, you’ve done it!”
Know what you will do with the items that don’t belong in that space before you start. Dealing with these items should be part of your project – as long as they don’t expand the scope of your project. For example, you might need to move some items to the garage from the room you are organizing. If the new space is organized, then go ahead and put those things away. But if it’s not, it’s okay to put them in a holding place until you can organize them there. (See last week’s blog post about the domino effect.) The point is to come back to the project you started, not to get distracted by another space.