Reddit reviews i-baby Portable Baby Carrycot Easy Carry Traveling Bassinet Infant Cot Cradle Baby Crib Folding Cotbed Sleeping Basket

Have several swaddling blankets to use in rotation, and learn how to wrap them properly. Also always have at least 2 burp clothes within arm's reach at all times, preferably already on your shoulder.

If you plan on walking anywhere outside with your baby, make sure to get a good stroller cover, even if it's just a dedicated blanket (make sure it's a decently heavy one to block out the wind and to stay in place).

A light wool hat/toque, and keep it on all the time.

Not necessarily a winter thing, but IMO a portable bassinet is great if you go visiting a lot. Get baby used to sleeping in it at home for alternating naps (even just in the crib), and then when you are out of the house for nap time, it is a small piece of familiarity that will make it so much easier to get them to sleep and set them up for success when they get a little older and you want to drop them off at the grandparents overnight.