Have faith and trust in your trade plan Follow your trade plan irrespective of the price you wont be regretting
One possibility - Define your initial risk on the trade. Take part at X multiples of that risk. Pull your stop to B/E then trail the stop on the remainder a certain amount. ATR functions work well for this. The ideal moving average length and ATR multiple can vary based upon your objective and how good your entries are in terms of maximum adverse excursion. This is the best way that I know of to let your profits run - the third cardinal rule of trading.