I don't have any friends who tow a trailer, however Young Drivers taught me what you mentioned about foot off accelerator, coast towards the stop sign and gentle with the brakes. I also know not to brake in the corners, steer into the skid if necessary and look where you want to go, etc.
The main problem for me is going down hill on icy conditions and coming to a safe controlled stop at the bottom, or even on a level road there are a few intersections near me that get covered in black ice due to our proximity to the ocean. I never accelerate down those hills, always coast, but as mentioned I am forced to ride the brakes which then cause me to skid a little bit.
Young Drivers never once mentioned shifting to a lower gear to help with coasting down hill, but I'm definitely going to give that a try when it's nicer out. I work from home so I'm fortunate enough to not have to go out in most storms, but there is still the odd occasion where I have to go somewhere to pick someone up or for appointments.
I'm curious though, on the newer cars that have traction control and winter modes, do they help A LOT or just a tiny bit where most of the skill is still required from the driver?