Many in my Hispanic fellow community need help desperately in this regard; they're horrible non-tippers (for the most part). It's caused largely due to the culture in many of our countries of origin where tipping just doesn't exist.
I know that in our Spanish congregations there's usually a big article on tipping whenever assembly time rolls around, in order to educate us all in the importance of tipping. I make up for it by leaving 20% tip in most cases, also by educating my fellow hispanics whenever I get a chance about tipping practices here in the USA.
DY