Focus on the A1 Word List. The exam strictly uses words from this list.
Don't just read the PDF. Use it as a simulator. start deutsch a1 modelltest pdf
The Goethe-Institut offers in PDF format on their website. Go to their "Preparation" section. This is the most accurate mirror of the real exam. Download the PDF, plus the audio files for the listening section, and the answer key. Focus on the A1 Word List