I seem to hit a plateau every 30 pounds or so. The last one lasted nearly six months

It's frustrating, and usually at some point I just throw in the towel and maintain for awhile, which makes it last longer. The good news is that I haven't gained anything back during those maintenance periods.
I broke my last one by cutting carbs back even more and really upping my protein intake. It's a hard diet for me to stick to, though, so I've done a little backsliding already. I'm trying to find a balance right now that will let me move forward without feeling like I'm starving all the time.