Sorry if this is too late!
Im 17 and hoping to go to dance school next ear, but i teach year 7, 8 and 9 voluntarily dance at my school.
Heres some ideas which I have used...
I am working on a show with them at the moment, and I have put together a short song edited of 4 different tracks which they dance ballet, contemporary, jazz and street to. I edited them well together so it sounds ok, but this can help you demonstrate your skills in all areas, and creativity, giving about 20-30 seconds for each section. The kids wont get too bored either!
When teaching contemporary, if I feel they arent putting enough emotion in their dance I make them stand towards the wall with their eyes closed and play the song, telling them to think of something that reminds them of the song. Then make them dance it again.
I also will do improvisation (in twos) from the corner, usually on a high level form the right corner, and floor work only from the left corner.
You could also progress in styles during the lesson, e.g. doing a jazzy cardio warm up, then focus exercised that are ballet based. With it being young girls, ballet is always a good one!
Use up to date music, not necesscarily your taste, but what you think their taste will be! But nothing too cringey that they might hate it. Here are songs Ive put into the peice for my kids at the moment = Catch and release (matt simmons deepend remix), to build a home (cinematic orchestra), beat it (MJ), and no money (galantis).
I also give them cards. I have 4 lots - actions space dynamics and relationships. Each couple get one card from each pile. You can either help them then choreograph a short duo inspired from these, or teach them a short section of choreography and get them to identify which from the cards can apply to it.
Another good one is using twister - each dot can have an action space dynamic or relationship on it. Once they are all tangled up in the game, get them to write down their dots and create choreography.
The last idea I have is bringing in materials, e.g. cloth, or objects, to base a dance on. They could even use large peices of cloth in their dance which is always fun and a bit different.
You could also show them some stuff online, videos etc, see what they react best to and give them choreography based on that style, so your prepared for each style but know your giving them what they want most.
Hope this is of some use...
Claudia x