As for my reminder, I memorize my family crests here.
Right: My father’s family: 丸に抱沢瀉 maruni idaki omodaka; (Face to face omodaka leaves and flower in a circle)
As for kimonos, put 5 kamons (one on back, two on chests and two on sleeves) are the most formal. Black tomesode has 5 mon crests but since Emperors family don't wear black tomesode, when you are invited imperial family, you shoud wear colored iro-tomesode and put 5 mon crests on it. It must cost a lot!