We have found one of the easiest ways to organize your garage is to install peg board on the walls of the garage. This will allow you to hang a lot of other things that may otherwise be on the floor. It is a great place to put things like tools and bikes.
Another suggestion we have is to get a bunch of plastic bins that you can store everything else in. You can put like things in the bins, label the bins, and then stack them against the wall. We know if you do these two things you will have enough room to park your car inside the garage where it belongs.