The only real 'rule' I've followed consistently in gameplay is that committed and married couples don't cheat or divorce. I've never felt a need to use a money cheat either in gameplay. However, I do cheat money needed for contest/challenge builds but that doesn't apply here. Again, I never cheat for satisfaction points, aspiration, skill goals or use freebuild to get a lot my Sims can't afford either unless it's needed/allowed for a challenge.
The majority of my gameplay saves start out as Rags to Riches too, but not all of them. Most times my Sims have a favorite color and I dress them and their homes to reflect it. I also like to alliterate their names, for example; Ben Bummer, Clarissa Coles, Delilah Devine, Hollie Hobbs, Jonah Jett, Lilah Lockhart, Gloria Gamble, etc. But not always, it depends on their character in the story or challenge.
I do have a lot of rules in building for myself that I like to follow. For instance; every bathroom has a toilet paper roll, every sink has a hanging towel and soap dispenser, every outside door has a rug in front of it, living room sets and beds have rugs too. All landscaping plants/trees/rocks/furniture need some kind of dirt/sand/gravel under them. All stoves have a hood, if they have a fireplace, they have a chimney and I always put tile under fireplaces.
If my Sims have a garden, they always have a garden hose and the rack with gardening implements. All hot tubs have the rug that looks like slats surrounding it. I rarely accept invitations via cell unless I'm trying to get the two Sims together in a romantic relationship and only if their needs are in good levels. I always mute their cells so calls don't interrupt their sleep. I never use the high chair for toddlers. I will sometimes get the umbrella rack for decoration, but none of my Sims actually use an umbrella. They're just a glitchy nuisance for my Sims.
Looking back on this I guess I should've picked 'I have an average amount of rules' instead of just a few. lol *shrugs*
Happy Simming! <3