Top 5 Pieces to Transition from Fall to Winter

1. Fleece-lined leggings

You live in leggings and can't imagine having to change out of them once the freezing weather hits. These leggings will allow you to put off wearing pants until you absolutely must. 
This pair from Anthropologie is $18 and comes in black or grey 
2. Hooded Scarf 
Sometimes the weather changes quickly and you can't prepare for everything, so if you wear this scarf it's okay that you forgot to bring your hat. 
This one from Urban Outfitters is $64 and comes in black, grey or purple. 
3. Shearling Ankle Boots
Instead of wearing your stillettos to look long and lean when you go out tonight, lace up a pair of heeled hiking boots. Though they are likely impractical for actual hiking, the shearling lining and textured sole make an adorably sensible alternative to getting frostbitten toes or slipping on sleet in your usual going-out heels. 
These boots from DSW are $45 and come in brown, black or grey. 
4. Patterned Sweater Tights
If you plan on wearing skirts or dresses through fall and winter, then you're obviously going to a have a pair of tights underneath. Unfortunately, for most people a thin black layer of nylon over your bare legs isn't an adequately insulating (it's also boring!) These tights are both a fun and comfy addition to an outfit.
These pairs from Modcloth are $25 and $24.
5. Oversized Blanket Cardigan
It's that kind of weather where all you want to do is snuggle up under a big blanket with a hot bad you have an 8am lecture. Luckily, this sweater pretty much doubles as a blanket so you can get cozy in class. 
This first sweater is $74 from Asos and comes in green or black; and the second one is $74 from Urban Outfitters and comes in ivory, taupe, green or red.