I took up contra dancing after many years of "Modern Western" square dancing as well as occasional folk dancing, round dancing, etc. After about a year and a half, I began writing contras and started calling at open caller nights. Since then, I've since called numerous full evenings and written well over a hundred contras, many of which I've since discarded. Here are my current dances.
One aspect of contra dancing I like is that its choreography is constantly evolving and changing.
Modern contras, since the 1970s, have emphasized being very accessible and zesty, sometimes inducing an almost trance-like state among the dancers and musicians due to their strong flow and almost continuous activity coupled with repeated sequences, live music, and high energy.
There are relatively few web resources on contra choreography. One of the best and most stimulating is Cary Ravitz's treatise, although he does assume some basic knowledge about contra's musical structure.
Once you have a working knowledge of the basic figures, structure, progression, and have identified some transitions that you think flow well, you can start writing dances. Here are some thoughts on writing glossary dances, moving beyond glossary dances, and various compositional techniques.
A special case of a glossary dance is the first dance of the evening.