So now your system has:
You can also have Take Profit Rules and Values, if you use a take profit and you want to move it from its original position.
Anyway, that's what you need for a trading system. Pretty much. Not really rocket science. On the other hand, far better than buying because the newspaper said so and having no defined point of exit.
But there's a couple of bits left. One is Money Management - how much money to risk on a particular trade.
There is also When Not To Trade Rules, which I refer to as holidays. Even if your Entry Rules are signalling a trade, there might be specific times of the day, week, month, or year that you shouldn't get in.
And then there's equity curve analysis - is this just a normal drawdown the system is having, as all systems do, or has the system stopped working altogether? If it's still there, have a look at this chart on the Collective2 website. Gained 500% in a couple of months. But now? It's fallen back to a 100% gain. Is that a drawdown or failure? Stop using the system and bank the 100%-odd profit, or stick with it? Get this right and it won't really matter what rules you use for everything else.
[Edit: That system had a 100% profit at time of writing, then a few weeks later it had gone to a roughly 50% loss.]