Well we have a simple solution to your problem!

Get in the car and put a small mark or piece of tape on the lower rear window to show the position of your hitch.
Now hitch your caravan to your vehicle and make two small marks on the window of your caravan so that they line up.
Now all you have to do is to line up the marks when reversing and you should be able to line up the caravan with ease.

Line up your vehicle every time