What should I know when using Uber for the first time? Any unique tips from veterans and drivers?

I don't know about unique. Just be polite and respectful. Don't leave trash, vomit in car, get food all over or put your feet up on the seats. Tipping isn't mandatory but GREATLY appreciated even if it's just a few dollars. 

People who drive Ubers, at least UberXs, are normal people.  People like you and me.  They often have other jobs. They may not have been doing this for years and years.   Know this and understand this.

- They will heavily rely on the GPS.  They may not know the roads as well as the cabbie.

- Their shift may end so if they need to cancel a ride or not accommodate your change request, don't get mad.  They have a family to get back to and other obligations.  They often work on weird schedules.

- Treat their vehicle with respect.  That car you are riding on may be the car the driver's kids or grand kids sit on. Don't puke on it.  don't leave crap on it.  Treat it like you treat your own car.

Respect your driver.  really.

Be prompt.  Be on time and be at the location.  You really should be at the curb when requesting one.  There's no excuse as you know we are coming on the Uber app.

I know newbies do this.  Once you request a ride, do not move.  Please for the love of god, don't move.  We can't see your location over GPS.  No, the blue marker doens't move on our screen It's only on your screen.

thank you.

Here are my tips to complete newbies. 

- When the driver is approaching, make sure you know what the car is, what color, and what the license plate number is.  It really helps you to be able to identify the car.  Remember the driver has no idea who you are, as they don't see much information.  It helps if YOU can identify them!

- Don't call the car until you are ready.  or just check how far they are, and make sure you are ready.  This isn't an oldschool taxi.  Don't let them wait.

If you let your driver wait more than five minutes, you can be dinged a no show fee of $5.00

- We understand cancellations happen.  Make sure you understand what the rules are.  If you cancel 2 minutes after you are connected with a driver, you will be dinged a cancellation fee.

Yes, the tip is to tip your driver.  Even a few bucks will help. ...despite what some people say.

Even tip the short trips.  Those are the ones where the drivers get burnt on.

Payment is done through the app, no need for cash :)