I had it with my first pregnancy two years ago. I'm pregnant again and, at my first prenatal appointment, my doctor did say that my chances of having it again are higher than average. I don't think there is anything you can to do prevent it besides being a healthy weight before pregnancy. This doesn't always work, though, as I was 5'3'' 115 pounds and 25 years old when I was diagnosed the first time at 24 weeks pregnant.
This time, I have opted to check my blood sugar daily for the entirety of the pregnancy, as it is not a big deal to me and gives me piece of mind. And I really hated the glucose tests, especially the three hour of course. Last time I had GD, it was very easy to control with diet, thankfully. So far, I shown no signs of it yet and my sugars have been good, but I'll have to wait and see.
Good luck, hopefully you won't have to worry about it at all this time around!