Nansi Shahri

Mordern and contemporary dance are not different. Contemporary has it's history with George Balanchine. George Balanchine is the one who created contemporary dance form in America. You can check out about him on google and his contribution in this dance form. Lastly, the contemporary is a mordern dance which belongs from the same ballet family. What I mean is the teachnique used in contemporary has it's origins with the Ballet dance form.

Most importantly you just don't learn dance. You learn the culture. A classical dance form represents an ethical way of living life. You get to explore so many things and trust me there will always be an answer to your questions in a classical dance forms. Because it's origins are deeply rooted with our way of living. 

Congratulate them first for their amazing performance and then wish them luck for their future. Also, it will be great if you want to tell them how you actually felt about their dance performance. Learn some tips to work out better on yourself. And stay connected with them because they will teach you amazing things that you can never think off.

It requires a vision and imagination of various movements dancing inside one's head and then we try to adapt it by practising, again and again, to make it happen.
The first thing we need to learn is musicality. Music gives you the right feeling which allows your body to groove. It gives you a vision/ imagination that gives you a cue. The second thing is your movement. Before choreographing a piece we improvise the movements with the music. This helps us to create and add new steps. The third thing is to practice and check the dance routine you created and if you would like to change some steps go for it. 
And this the routine a dancer/ dance teacher/ choreographer follows :)