Garage door insulation?

What do y'alls do about garage door insulation? Not so much the materials but specific tips, tricks? Here I've hung blankets and used pieces of wood to hold the blankets down and the door closed. Also a couple of small clamps and blocks of wood wedged in the track to hold the door closed. Probably not as effective as proper insulation but I want to say these big blankets were $4-6 on sale. Spending just a little time in an unheated garage as an adult you quickly realize how thin the walls are and how drafty it is, at least this one. Proper insulation takes quite a bit of work I think. For now focused on sealing the gaps. I may lay cellophane or saran wrap over the edge of the side door and 'reverse-mold' the whole door frame in with cans of foam, but there's always a fine line between making a difference and wasting time.

It isn't even supposed to be cold here, but it is about 1/4 year aka 'turn' past the shortest day of the year. Near the coast as soon as the sun goes down you instantly feel it, most right before sunrise. Instead of 2x4s, although I need to finish the insulation, walls should really be made at least 12" it seems. This could be with the same amount of wood, only sectioned thinner.

Is the exterior trim sealed to the door? Like this?

another pic:

I found that helps a bit, but it's still a garage door so some level of draftiness is to be expected. It's the main reason why I want my shop door to be swing doors - they can seal better.

^ I need to install some of those. I think there are several layers that can or need to be sealed to prevent drafts, for example gaps in the plywood and construction materials, and then how many layers of vapor barrier are used, which might depend on the building codes or specific application.

The guy we bought our house from used 1/2" foam sheet insulation with a reflective film on one side. He cut pieces to fit into the recesses on the inside of all the sheet metal garage door sections and then taped it in place, two layers. It seems to work pretty well, it's cheap, and it has gone up and down with the doors for over 20 years.

^^^^ This is what did for the house garage as the door was just metal, resealing the edges helped a lot but the one thing that made a clear difference was replacing the bottom door seal mine was hard as a rock.

IMO it's not one thing but a number of small things that add up with roll up doors.

I bought sheets of foam 1" hard insulation from Lowes and slip fit them in.  Really improved the temps in the garage on the cheap and doesn't look terrible.