That's an old truth that your name is the sweetest word in the World to you. Apart from this method, Associations(Mr Z looks like my Maths teacher and Ms B sounds like my neighbour) and Impressions help a lot(you usually spot something bright or suprising about the person you meet for the first time: e.g. like Mr Green is the guy with the wig, and Ms Blue is the lady who talks too fast etc. ). The best thing is to combine these 2 methods with the Repeatition and polish them with making up a Story about the group -but that's more to remember the people for lifetime:).