To use a first sentence generator effectively, follow these steps: 1. Choose a reliable generator tool. 2. Input your desired topic or theme, if applicable. 3. Generate multiple sentences and read through them. 4. Select the most appealing or relevant sentence. 5. Use it as a starting point and expand on the idea. 6. Refine and personalize the sentence to fit your unique voice and story. Remember, the generated sentence is a springboard for your creativity, not a final product.