Great advice and comments given here already. (edit: Especially ^^^)
The week before i picked mine up (a couple of weeks after i passed the course) i was driving in the car on a nice sunny afternoon- and up ahead i saw a bunch of dust and vehicles pulling over way off in the distance....as i approached i saw it was a motorcycle accident that had literally just occurred. There were plenty of cars pulled over assisting and people with phones out and i didn't actually see what happened so i carefully drove past on the shoulder and tried not to be a gawker. I won't go into graphic detail, but the rider died (it was pretty obvious).
I'm a fan of gore and horror, but i was totally shaken by it. All the way home- trying to decide if i should tell the wife what i had saw---or if that would just cause her to worry about me even more.
Anyway---
Whether you want it or not- the image is burned into your mind. Use that to your advantage.
i think i have a healthy amount of 'scared' when i ride. Probably better word would be cautiousness. No matter how confident i get.
If i forget- a slip of my rear wheel on some gravel in a overly quick turn or an old lady will pulling in front of me from out of nowhere and i'll be reminded very quickly.
There are plenty of guys on these boards who have never been in an accident in many, many years of riding- so don't assume it is inevitable- or it likely will be.
Gear, no booze/drugs, no (excessively) tired or angry rides. Get out of blind spots, block wisely, eye contact when possible, ride intersections with other cars blocking for you when possible, better to take a turn too slow than too fast, extra careful of drunks at night and sleepy, distracted drivers in mornings. Be a courteous driver to others. All the good **** people have already said.
Practice in safe areas until you are 100% sure you are ready. I know guys who have been riding for over 10 yrs who still occasionally hit the parking lots to practice. Don't let other riders dictate your speed if you ride with a group.
The meditative quality and the constantly changing sensory inputs (sights, temperatures, smells, speed) are really addictive. You'll think about it when you aren't doing it- and look forward to the next time as soon as it ends.