1. Choosing the most direct route to and from work, which put me on high-traffic streets with people in a hurry. Research your route well, and be willing to add extra miles to take advantage of quiet streets, parks and campuses.
2, Locking the bike in a hidden, off-the-beaten-path site. I learned that visibility and high foot traffic is safer.
3. Forgoing fenders and rack, thinking they were uncool and would slow me down. Getting forced into an oily puddle changed my mind on fenders, and the gift of a pannier showed me what a relief it was to get the laod off my back.