Here are some of the small lessons I have learned so far in biking to work:
1. A bandanna is very useful. Keep one on you at all times.
2. Wear sunscreen.
3. Always check the weather for the day, and have a back up plan in case it changes.
4. Keep a roadside emergency kit. Mine includes:
a. an extra tube
b. tire-changing tools
c. fix a flat
d. a bicycle pump
5. Invest in a lightweight, good quality rain jacket