not telling anyone where you are going or leaving a note is a biggy
your clothing list looks different then what I would choose- cotton t-shirt, cotton sweatshirt- cotton kills is a mantra that is based in fact- add in strenuous activity and cold temps it becomes more so
a good base layer top and bottom is where it all starts- merino wool or synthetic- something that wicks and dries quickly. over that a thicker wool or syn piece- on the outside a wind/moisture proof layer (top and bottom)- add and subtract these layers as the activity dictates
in your pack (you always go w/ at least a small pack) is your insulating layer- down or syn filled coat/vest- this can be put on at rest stops (or save your butt if your caught out)
getting turned around happens to all of us, a map and compass (and the know how to use it) gets us un-turned around- a gps (and the know how) can be added to a kit
also in that pack you didn't have- is a emergency blanket/bivy in the unfortunate event one gets caught out- there is also food, water, a small stove, cup- the ability to melt snow in the winter is very important- a hot drink or meal can be very beneficial as well
in that pack goes a small first aid kit in the event your injured (or even your dog)
lots of folks forget sunglasses and suncreen in the winter- I've seen some terrible burns in the winter- no sunglasses and snow and sun can be very dangerous
you didn't get lost, but if you did- did you have any way to signal- mirror, whistle, cell phone (a smoky fire is better than nothing)
on the plus side you had fire starting material, a good knife and the know how to get back to square one