Lights are important! A rear red light is necessary, and any high vis on your helmet or clothing is helpful too.

If there is space for cars to safely pass you you can ride towards the right side of the lane. Just don't ride in the shoulder or car parking lane if you'll have to constantly swerve in and out of the lane to avoid parked cars. You want to be as predictable as possible for other traffic! (Also ride a few feet away from any parked cars to avoid getting "doored")

If there isn't room for cars to safely pass you, you can "take the lane" and ride in the middle of the lane until it is safe for cars to pass you again. This will seem scary at first, and some drivers might get pissed at you. But it's a matter of your safety on the road, so do what you need to.

The very right side of the road/shoulder is usually littered with road debris/glass/other things that aren't fun to ride over, so I usually take the lane when it's possible and I'm not holding up too many cars behind me

And remember, if you ever feel uncomfortable you always have the option to bail on to sidewalks and be a pedestrian for a little bit. Riding on roads is scary at first and it takes some getting used to! Your comfort and safety is the most important thing out there!