I've never done a single exposure star trail, I've only tried the stacking method. I don't know what kind of Aperture and ISO settings would properly expose an image with a 30 minute exposure. That's a ton of light! It may even require a neutral density filter...

Anyways, try leaving your camera locked shooting on continuous mode taking 30 second exposures. With your shutter remote locked down it will take them over and over as long as you leave it locked. The longer you leave it locked the more images you will get and the longer your trails will be. An hour would be good trail. Hopefully I'm making sense. Play around with your settings and your composition until you get an image you like, before you leave it out there for an hour. Try shooting with your aperture wide open. (For my garbage kit lens that's 3.5 when I'm at 18mm) and try ISO 800, and just use auto white balance. Remember to turn off noise reduction. Also later on you can try shooting in RAW so you can adjust each frame's white balance and tone to your liking in Lightroom. Here's a link to a video explaining the program StarstaX which you will need. (super intuitive program!)

How To: Star Trail Photography - Stacking - YouTube

Good luck!