If you want to be comfortable for an extended period the key is to have insulation everywhere.
Find boots that keep your feet dry and warm, use thick socks. You can cheap out on everything but boots, buy good boots.
Get two layers on your legs, long underwear and pants might cut it, but ski pants make a night and day difference.
Find a coat that is not drafty, if it is not warm enough, layer sweaters and long sleeve shirts until it is.
Toque (I've heard them called beanies) and scarf. Always cover your head and neck.
Gloves or mitts, go overboard on these nothing ruins your fun like cold hands. Wool is always warmer than it looks.
I touched on layering a few times, if you are not familiar with it it is the secret to staying warm (and comfortable, if the day warms up you just shed layers). Layers trap warm air and become more than a sum of the parts, for your core you don't need high quality attire, just something to block the wind and a few layers to trap air.
Seconding much of this advice, especially high quality attire for the feet and the head. See also Suvorov's famous saying: "keep your stomach hungry, your head cool, and your feet warm." Russian flappy "Ushanka" hats (especially from real fur) are amazing. I am still trying to figure out a good compromise between hand dexterity and warmth, probably some high tech skiing gloves exist for this.
Qualifications: once visited relatives in Novosibirsk for Christmas.
edit: re: gloves: you know, it occurs me a simple thing you can do is ha...
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