Caldad has some good points there, especially the watching of others.
What catches many drivers out is by not taking note of what they are driving, and how close the ‘pivot point’ is to the back of the vehicle before they start.
Generally there are 3 standard trailers, we’ll ignore tanks tippers and extra length stuff, and those with steering axles for this.
Beware the empty tri axle with automatic front axle lifting, very often you can pick one up and be backing in fine, then half way through the manoeuver the blasted front axle will lift, that changes everything, its suddenly become a very long wheelbase tandem.
A single axle trailer will usually be short (wasn’t always the case, awkward buggers long singles), if you get one you’re usually going somewhere tight, it will obviously pivot on its one axle at all times.
A tandem (any length) if both are fixed axles will pivot at a mid way point between the two axles.
A three axle trailer, usually full length, should pivot at the middle axle point.
Tandem and three axled can and will change their pivot point mid turn if you reverse over uneven or slippery ground as one axle grips more than another, so keep an eye on terrain and surface.
The point i’m making is this, look see where the pivot point is in relation to the back of the trailer before you start your manoeuver, if you’ve driven the vehicle to the destination, or on the assessment you will already have an idea how much you need to allow for the trailer to follow you.
If you need to exaggerate your line to stop the trailer going up the kerb, than its sure as eggs is eggs that you’re going to have to do the same when reversing.
If it follows your line easily, then chances are its a 3 axle or and is pivoting about 2/3rds down the length of the trailer so whilst it turns easily you have the added problem of rear end swing.
A short two axle is the ideal, they’ll go anyhwhere.
On a tandem or three axled trailer the rear overhang might not look much when measured from the rear mudflaps, but when you look at the real rear overhang, as measured from the pivot point, its an awful lot more, and this must be taken account of.