Choose a few meaningful fields
Record food, appetite, litter observations, weight measurements and unusual behavior when relevant. A short consistent record is better than an elaborate log that nobody maintains.
Keep measurements comparable
Use the same units and note the date and context. A weight taken with a different scale or at a different time may not be directly comparable. Preserve the original measurement.
Separate observation from interpretation
Write what you saw before guessing why it happened. Specific descriptions help a professional assess the situation. Photos or videos may be useful when collected without distressing the cat.
Share only what is needed
Keep private information and veterinary records secure. The local tools store information in your browser, so export anything you need to preserve before clearing browser data.
A useful next step
Choose one manageable improvement and make a note of what changes. Use the practical tools to organize the details, and return to the discussion to share what you learned.