Nerves of steel indeed. I never sell my coins for less than I payed for. Do it the same way. If I am not quite sure about a coin I buy a bit. If the price drops, I buy some more etc. Always watch the charts for the support and resistance levels. If price shoots I sell a little bit. If it shoots higher a bit more. If I earned the money back that I invested in it I keep it until i think I can sell.
Works out just fine.