As I'm going through an axle replacement right now here's what I've learned.
Here's my 10 rules in no particular order:
1. Know the load you're going to carry.
2. Know the rating of the trailer NOT including the trailer.
3. Get a full deck if you ever want to use it for other things beside hauling your Cherokee around.
4. Don't go less that a 30% safety factor relative to your load.
5. Don't go with a box frame style, go with open 'C' channel as rust in Michigan will destroy a trailer in 6 or 7 years. Aluminum trailers simply not worth it and difficult to repair if they crack.
6. Get the trailer rust proofed if you intend on keeping it.
7. Get good lights, LED preferably as voltage is less and they don't fail from shock loads like regular incandescent do.
8. Get brakes on both axles if the load warrants it.
9. Don't get as beaver tail as I have yet to see where they don't drag in and out of driveways and it's not like we need gentle approach angles to get our vehicles loaded which is what a beaver tail is for.
10. Stow your ramps, don't make them hinge at the rear. There are many times you need to hang something off where the ramps get in the way when they are folded up. Plus there's the wind resistance issues just discussed.
I throw a picture of mine up tonight.