Every religion and ethnicity has different ways to ward off the evil eye,  and honestly, you can't say which one of them is generalizably the most effective. But being a muslim, a practicing one, I believe that reciting verses from the Holy Book (Quran) provide protection against the evil eye to us. The Book itself mentions the existence of evil eye so having recognized its presence, what could possibly be better than the divine verses? 
Otherwise, in the hindu culture it is a custom to burn red chilli on the stove (or wherever) and take it around the place or the person who you think is affected by the evil eye. Then they will be safe by it (accoridng to their customs).