-Firstly... MAKE SURE THEY REALLY ARE GOING TO COSPLAY WITH YOU... I hate when in the end I'm the only one that did my cosplay... -_-... It really sucks...
-Secondly... Pleaseeeee let your friends choose the character they like, otherwise they will be kinda mad in the end... (Please help them choosing the right character for them).
-Thirdly... You and your group of cosplay should stay together in a Convention! (-_- It sucks when you are in a ''group'' and then they spread out and you don't freaking know where they are until the end).
One more thing... HAVE FUN!!! ^-^!!!! Have a good moment with your dear cosplay friends. <3