Learn your city
You've been out and about and are hopefully comfortable on a bike. There's one last piece to riding safely: know where you're going.
By this point, you've probably seen the green painted lanes, bike signs saying something about 'Green Wave', and maybe watched a confident biker weave right through a set of cars. These are all suggestive of the well documented bike lanes that can take you safely all of the city. Knowing them is like having a whole new set of roads to plan directions on.
Today, pick a few desitinations that you like to visit. Next, use Google Maps to route to those spots via bike directions. Notice how they're a little different than driving directions. Most map apps try to follow safe bike routes when possible and it's a good idea to get familiar with them to better avoid traffic, enjoy safe riding speeds, and see other bikers. If you're in SF, look into: The Wiggle, Polk, Arguello, and Folsom.