I wipe the pan with lemon juice on some kitchen paper and then rinse with cold water. It gets rid on any residual taste. You mustn't leave any residual lemon juice in the pan

It depends on the heat you are using. Non stick should not be heated over very high heat.

Not if you don't scrape the bottom with the tines of a fork (which some people seem inclined to do).

Absolutely not!

The only thing that will ruin a non-stick pan is using any metal utensil, or a metal scouring pad, on it. Stick to wood, nylon, or silicone spatulas, and you'll be fine!

No, not at all. Just wash it out..it'll be fine.