until you feel comfortable assessing the potential profit range and likely play-out timeline for a move, better stick to hard & fast rules for exits / scaling out / moving stops up to break-even / trailing stops etc. initially its not a bad idea to simply close 80% of yr position when you hit your TP target or at whatever level you are within the timeframe you've given yourself for the move to materialize (even if a loss), and let the rest run with an appropriately defined trailing stop (again set a timeframe otherwise your just gambling...)
Wherever you set a stop, it's ARBITRARY. However, some places are more logical than others. You want to give your trade "breathing room" but exit on some indication the upswing is *possibly* over. Two I like, (a) break of bottoms line, and (b) break of prior dip low.