I actually had this discussion today with a trader. He said that one of the most common things with trading tips is that they always tell you to when to buy but never when to sell. Having preset exit points is good but keeping to them is something else. Newbie traders often don't make it because of greed. If your existing trade goes green it's always tempting to keep it open for 'just' one more day. I think that that's something that isn't covered enough.
If it went already green, just set a trailing stop and you're fine for that trade. Trailing stop just follows the market growth, and if it turns down, it automatically liquidates your position preserving the accumulated profit. Problem is that Kraken has stopped using these kind of "smart" trade methods. The official reason was that their system was heavily overloaded and they can't offer this kind of service for a while (I hope that they're upgrading their system and it's not final...)
