Next thing to try would be to forward test it for a while (i.e. use NinjaTrader connected to your real time data feed, but without doing real trades), and see how it does ... or maybe that's what you mean when you say you have already used NT 7's "simulator"?
... if you are still happy with it, next try for real, doing real trades ...
If things don't work out as anticipated (i.e. if the hoped for performance doesn't materialse), it's a good learning exercise to try to figure out why ... as intradaybill hinted, "statistical (in)significance" and "fooled by randomness" are all ideas you may need to learn more about ...
Will help you make a better system the next time round.