Tips, what is the "right" way to do it's in Zihautanejo.

Tipping taxi drivers- No tip if they charge the "union"rate. 10-15% if they charge the real rate. Ends up about the same.
Restaurants. I am a big percentage tipper at little inexpensive places if the food and service are good. In the fancy places, my percentage goes down to around 10%, following the lead of wealthy Mexicans. Baggers ands kids at the mercado who help you- 5-10 pesos depending on what they do. I usually have 1-2 bags at the supermercado-how much is that worth?