I used to have the same problem. My wife's car went in the garage and mine sat outside in the driveway.
Most of the clutter was long handled stuff like yard & garden tools, shovels, rakes, brooms, etc. that were leaning in a corner and falling down all the time, taking up more room on the floor.
I put up wall hooks to hang all those on the walls. Huge improvement.
There was also a bunch of small stuff, hand tools, boxes of nails, shoes, etc. that got sorted - many got pitched and the rest went into a storage cabinet in the basement (I picked up a 3-shelf storage unit with doors @ Menard's for 40 bucks and it held ALL of this small stuff)
There was also a bunch of "medium" sized stuff, like gallon paint cans, gas cans, tackle boxes, a spare tire, some 5-gallon buckets, etc. I put a bunch of 14" wide shelves along the one wall (three of them, plus the floor space under the one made 4 places to put stuff), and put everything there.
ALSO, a few years ago I bought a 200 dollar plastic molded storage shed that goes outdoors, some of my bigger stuff is in there (patio furniture, chainsaw, weed eater, etc)
Human nature is to store things on horizontal spaces (the floor, the top of the freezer, any table that happens to be near, etc)
Big shelves "stack" those horizontal surfaces so they take up less room.