Not much room in the garage on either side of the car

[M A V I C]

I would suggest practicing. This way when you have to park in a similar small space, you will be able to do it more easily. Many places near me have parking spots that are so small a full-size car is wider than them. My mid-sized car only gives me about 8-10" on each side. So when I park, I have 16-20" between me and the next car. I have to park it perfectly or I wouldn't be able to get out (or the passenger.)

But if you really want an assistive device, you nailed it earlier on. Hang a ball that hits your hood ornament. If you're too far to one side or the other, you wont hit the hood ornament.