Here are the corrections for the mistakes in the sentences provided:

1. **"How about go to the zoo?"**
- Correction: "How about going to the zoo?"

2. **"I think we should organizing a fun run."**
- Correction: "I think we should organize a fun run."

3. **"I buye d a book last Sunday."**
- Correction: "I bought a book last Sunday."

4. **"She likes eating fish so she also likes drinking water."**
- Correction: This sentence is grammatically correct, but could be clearer with punctuation: "She likes eating fish, so she also likes drinking water."

5. **"My father often spends his free time to read books everyday."**
- Correction: "My father often spends his free time reading books every day."

Feel free to ask if you need more help!