Also, when you learn a new strategy, you also need to learn the emotion to use in executing the strategy. Without learning the emotion, you will not be able to execute the strategy the way it was designed for, you will end up either abandoning the strategy midway (due to fear) or applying your discretion thus ruining the strategy.
If I have a new strategy, I test it on a live account (not a demo account) using 0.01 lot size to minimize any losses. I test the strategy for several weeks using a small lot size so i learn the emotions behind executing it, before i try it on a bigger lot size.