Still have my trailer stuck up the side of the house for the same reason.
The size of the trailer depends on the size of your round, mine has a 250ltr tank in it and I pull it with a 1800cc vectra.
Like Karygate said a Jockey wheel is a must as is a braked system also drop legs at the back are a great help when the trailer is unhitched, a lockable lid is also a must and to play safe an alarm system run by wheelchair batteries.
Towing is the easy bit, its the reversing when you need to take care and lots of practice at it and it will come second nature, until then Just unhitch it and swing it around.
One more important thing is to make sure your gear in the trailer is balanced for a care free tow, or you will find it snakes behind you, if that happens keep your foot of the brake and Just take your foot of the accelerator until the snaking stops, you will soon learn even with a balanced load what your top speed is before it begins to snake, on my car its 72 mph
Email me if you need any more help
