First guage a company based on it's fundamental value. You can use IBD or simmilar publication to do that. You probably did that other wise you would not pick this stock. Your first step was right but next step was wrong.
Once you are in, watch the price/volume action on daily basis. This falls into technical analysis. If the price volume action confirm that trade is going against you. Just get out at 8% stop loss. No question asked.(Majority people don't get out at 8% loss, thinking that it will come back to it's original price).
Also most important once you decide to buy, wait until the results are decalred. Never buy 2 week before the results are due. You may miss some run up as some stocks shoots up after result, but you can always get a chance to enter the trade after few days.