I recommend not trading and not selling. Just buy-and-hold and ride the ups and downs.
There's other alt-coins that are ripe for trading but.... I learned the hard way a long time ago and regret trying to make quick, easy money with Bitcoin. It will not cooperate.
That is what im going to do on the next big pull down. $4000usd per bitcoin can happen in a couple of days and $4500 by the next friday. It just sucks that its going so high that I cant trade it anymore.