I finished the Deutsch-Test für Zuwanderer! I took the first part on Friday (listening comprehension, reading comprehension, and writing) and the second part today (speaking).
All in all, I felt like it was pretty easy. The hardest part was the second section of the speaking test: describing a picture. But that was mostly just difficult because the picture was so simple. I had trouble coming up with much to say about it. In the end, though, I just rambled as much as I could using the most complex sentence structures I could think of.
In the end, though, I don’t think any amount of cramming could replace regular practice. The materials from the Goethe Institut will help you become familiar with the test format, but doing well in the exam requires some amount of comfort with everyday German. I feel good about it, but I’ll know for sure how I did when I get the results next month!