One thing about bikes and traffic is that it becomes much safer when you get experience, so be cautious getting the experience.
If you're from Pitt, there are a couple of cool, easy places to ride to.
It isn't too far (down Bouquet, Jonclare, then turn right down the valley on Boundary street to get to the bike trail. You can go downtown or to the southside on the trails, without doing too much road work. The hill on Jonclare is rough coming back up.
If you go to Schenley Park, the roads there are wide and traffic is low, for the most part. You can go up to Squirrel Hill, catch a movie, shop, or ride on trails in the park.
The back roads between Ellsworth and Fifth are good to get to Shadyside on.
In Oakland itself, be very cautious. Traffic is ruthless.
Be particularly careful on weekend nights. There are drunk drivers who are both rookie drivers and rookie drinkers - mediate on that thought for a moment and you might decide not to bike Forbes and Bouquet on Saturday at midnight.
Be careful, wear a helmet.
Others might not agree with me on this one, but if there is bad traffic/drunkards about, go on the sidewalk -but be careful to keep from being a hazard to pedestrians. Pedestrians own the sidewalk and you are a trespasser. (Drunk WALKERS are just fine by me.)
The sidewalks in Oakland tend to be too crowded to safely bike.
I'm never too proud to get off and walk my bike, if that is what conditions call for. (Well, sometimes I'm too proud, but I like to pretend I'm more righteous than I really am 
If you wanted to "train", find an empty parking lot. I use the Schenley golf course parking lot.
Practice two things - panic stops (back wheel starts to leave the pavement) and biking along a painted line on the pavement while looking behind yourself without swerving. If you ride in traffic, you will get a chance to use those skils. I'm older than dirt, but I need to practice both of those things more.
It amazes me how prolific I can get at popsting when I'm avoiding work.
Good luck
Mick