pakole: the advise I can give is: You will learn over time what you need.
Here are a few tips for ya...
Sand and Ice: Start braking early to allow for the increased stopping distance on slick roads. Take this opportunity to practice your cornering technique by braking early and coasting through the turn - just don't practice this at stop signs.
Debris in the Bike Lane: This time of year bike lanes are particularly laden with debris plowed off the roadway. Try using additional protection against flats and consider riding in the lane of traffic where the bike lane is unsafe. Report such conditions to the local street maintenance department.
Be Visible: Motorists must deal with fogged windows, poor visibility, and glare. Make sure they see you by wearing bright, reflective clothing and even using lights on overcast days. Good headlights and flashing taillights are a must for night-time or early morning riding.
Temperature: As any seasoned commuter will tell you, dress in layers. Start with a layer next to your skin that wicks moisture away, then go with an insulating layer such as fleece or a heavier jersey. On the outside use a shell to block the wind. To keep your hands and feet warm, wear long finger gloves and shoe covers - keeping your arms and legs warm help too. One common problem is to sweat and then get cold, so shed layers as you warm up.
Drink Up: You may not feel thirsty, but when you see your breath, that's water leaving your body. When it's really chilly out, some riders even start with warm water in their bottles - never mind the plastic taste.