When I first started to trade the forex market I was all "caught up" in this idea about having a trading system. It sounded so good to have a solid system to follow. No need to make any decision, just follow the system. Consistent profit over time. I even heard some banks use them.
Then I learned they could stop working. You would have to be able to construct a new one. You need to know when to not trade your system, for example during macroeconomic news. Perhaps you need two or more systems, one for trending and one for ranging markets. Full article: http://www.investordave.com/255-why-no-forex-system-will-ever-work