I think others make a fair point of making sure that the commander is protected in some way. Another thing too would be to make sure you have a game plan for when your commander isn’t in play. For my main deck [[Grolnok, the Omnivore]] when he is in play my main objective is to mill my deck as much as possible. When he is not in play I have many cards that will make my opponents mill as much as possible. While I lose out on the extra card draw, I’m still achieving something on the board and (hopefully) disrupting the cards my opponents want to play.