Depends a bit on how far you are riding and how cold of course.
Layers work best in my view.
Balaclava or neckwarmer for sure. The issue with a balaclava is how tight your helmet is. I wear a light balaclava all the time for tunes and have a neckwarmer along these lines. - the longer the bib front and back the better to seal.
Lots of glove options - I find the back of my hands suffer the worst and my thumb.
Stick with technical underwear - no cotton as if you sweat then you freeze with cotton on. Dri-fit stuff is great. Long distance - poly underwear is excellent.
A decent rain jacket can be a "last layer" option that does double purpose. I wear a bright yellow iCon and it's good even on cooler days like now.
Revzilla is excellent and you can return stuff no questions asked.
If you mention your bike type it helps as those with a lot of upfront protection like mine have a different situation to deal with than sport or naked.
Fogging can be very dangerous and balaclavas and neck warmers make it worse.
Also really depends on the distance. I've ridden at 6-8 degrees from PA in the rain and down near freezing locally with various layers and a few runs below freezing for very short hops to the store - leaks around the helmet and gloves show up right quick.
Longer runs you risk hypothermia so warm up breaks are good - just don't get sweaty.
