If you're just starting to use rules, I would suggest using them sparingly and making them all specific to situations where your team struggles.
My first rule was one for fourth and inches plays deep my opponents territory. I made the rule because I was tired of seeing my team settle for field goals after long drives, and then subsequently, missing way too many of them (this was before I had good weights for kickers, snappers, and holders).
I have used up to 20 different rules for both offensive and defensive game planning. Rules to run the ball with a lead, rules to switch to prevent defenses in the fourth quarter, rules to gain granular control over third down situations, rules to override my defensive game plan against specific sets against specific opponents (these come and go)...but for the most part, I've stripped most of my rules and am back to using just a few.
I'm not sure how much I care for the strategy because I'm missing some key elements of my rule build. I'll probably end up with around 12 rules that I use all of the time and then move defensive overrides in as appropriate. That said, I would build my entire game plan based on rules if I could import a CSV file with them.