For many stocks I base the my trades on f/a. So for example, on bad news, I begin scaling out of my losing position. Depending on the news, I may close out the entire position at a loss. For example, if a drug is not meeting end point requirements for FDA approval, I will start selling out, but may keep a very small position just in case it turns around. On a winning position, I will add to a trade, for example, company wins some patent victories. I may add to a losing position if my main stop has not been hit, but the position has moved against me in order to average into the trade. Another good idea is to buy when analysts say sell, and sell when analysts say buy.