How to remember...

So here is a new thing I have been thinking of doing called "how to remember". So during these I'll choose or take suggesting about any K-pop member in a group and I'll try my best to explain the qualities that make them different from the other members. I will be starting this sometime during the third week of September 2014. 

During the next. Please make suggestings on which groups or artist that you would like me to help you try to remember in how to tell them apart.