They'll make a road for cars and a sidewalk for walking, yet no place for bikes.
Ride slowly on the sidewalk, yielding to pedestrians
Ride on the road fast and cautiously
Obey all traffic signs
Use your vision and hearing, look both ways
Use lighting, especially on the rear of your bike.
Your bell is almost useless on the road. If there's a driver not paying attention, don't be afraid to yell.
Do not blow stop signs. This is the law.
Use the correct hand signals.
Bring water for longer rides.
WEAR A HELMET! I have had the air knocked out of me, scraped my face, and had numerous injuries cycling, and although I have yet to make use of my helmet, and I'm not looking forward to that day.
If you're in a crash, call 911 immediately, no matter how minor the crash is.
To add on, even if you're against helmets, don't criticize people for wearing one (think: karma). Also, though I recommend a helmet, perfecting safe cycling should be your number #1 priority.
https://bicyclesafe.com/ for more information
https://rideillinois.org/safety/bike-safety-quiz/ for a quiz on road safety