Previously I had started a thread on FF for a different strategy, it hasn't worked out, nor does it hold my interest as much as the idea of spreading or pairs trading.
The entire strategy here is based upon finding the leading pair and trading that first or finding the leading pair and trading the lagging pair in the direction. Pairs must be highly correlated and low spreads are a must, because the positions are not meant to last more than a minute or two. Or if you're lucky, even less.
The idea here is high volume, high speed trading. Closing trades as soon as you open them if the momentum suddenly runs against you.
Basically really short term trading.
Originally I'd trade both sides of the spread as well, but after a while I realized that it made the strategy almost impossible trading both legs. It has to be one or the other.
If you're choosing to try this, it is not for the faint of heart, it's extremely stressful and a good lesson in cutting your losses as quick as possible and making smooth and fast decisions to better your position in the market.
As for the rules:
-1 minute chart for two products, highly correlated.
-Line charts work better for me in this case as you do not need a constant MTF bias.
Really there are no more rules than catch the leader and then the lagger, and trade every time the correlation fluctuates. 
Remember, this is not about having the perfect market outlook or knowing where it's going to go, it's about reflexes, quick thinking, and the ability to strike a losing trade from the books before it snowballs out of control.
I will also add a Trade explorer to this later, live and demo. Very small for less risk.
Good Luck.
The entire strategy here is based upon finding the leading pair and trading that first or finding the leading pair and trading the lagging pair in the direction. Pairs must be highly correlated and low spreads are a must, because the positions are not meant to last more than a minute or two. Or if you're lucky, even less.
The idea here is high volume, high speed trading. Closing trades as soon as you open them if the momentum suddenly runs against you.
Basically really short term trading.
Originally I'd trade both sides of the spread as well, but after a while I realized that it made the strategy almost impossible trading both legs. It has to be one or the other.
If you're choosing to try this, it is not for the faint of heart, it's extremely stressful and a good lesson in cutting your losses as quick as possible and making smooth and fast decisions to better your position in the market.
As for the rules:
-1 minute chart for two products, highly correlated.
-Line charts work better for me in this case as you do not need a constant MTF bias.
Really there are no more rules than catch the leader and then the lagger, and trade every time the correlation fluctuates.
Remember, this is not about having the perfect market outlook or knowing where it's going to go, it's about reflexes, quick thinking, and the ability to strike a losing trade from the books before it snowballs out of control.
I will also add a Trade explorer to this later, live and demo. Very small for less risk.
Good Luck.
