I have been reading a lot and slowly formulating a trading system. I recently finished a book by Curtis Faith (The Way of the Turtle) who was part of the Turtle experiment. In his book he talks a lot about validating a system by back testing. This sounds great in theory and I have just been playing around with Amibroker and the feeling I get is that I could spend significant additional time understanding the product and adjusting all the configurable elements to determine the best trading system.

How have others validated their trading systems? Do you take for granted the indicators/systems suggested by others?

Do you paper trade? Do you use a system and then slowly tailor it over time?