Being a dual citizen and having more than one passport is still considered exotic in the eyes of many people. One of the things they are concerned about is how they are going to travel with more passports, which one to use and when.
However, there is nothing complicated about it, you just have to keep in mind certain things before you travel, e.g. if one of your passports is American or European, make sure you use it when you enter and exit these countries.
Long story short, make sure you understand the rules of a country you wish to visit and choose the most favorable option for yourself.