Draft rough scripts for a few episodes, and if possible act some of it out on video...
Having physical drafts and/or video will allow you to market it better, and very importantly make it easier for you to legally protect your sitcom idea from being "stolen" by those you pitch it too.
And of course consult / retain an experienced attorney in intellectual property law at the getgo.
Anyways, go for it - you never know, it could be a winner
Ron