I actually do basically have "house rules" that I play with. I never actually thought about it as setting rules for myself, I just try to play the most realistic way and the most fun way. I like to play games as realistic as possible.
On defense I only play as free safety because I find it the most fun position to play. I also play my position (if I'm in deep zone I don't run up immediately on runs or play near the line of scrimmage). I also do not change my player often (I will at times, but rarely and if I change my player during a pass I only go for deflections, not INT's).
I try to stay in my base defense as much as possible and do not blitz very often.
It is extremely rare that I scramble with my qb. I like to sit in the pocket and check down receivers. With the sliders that I use, you have very little time to sit in the pocket. Even if I try to scramble it is very rare that I am able to get away, and I pretty much scramble to get out of the pocket to throw the ball away. I don't even remember the last time that I scrambled and gained yards.
The one thing that I do is I use my whole playbook on offense. Mostly because it is more fun, more realistic, and because the CPU doesn't do a good job of making adjustments which makes it unrealistic to use the same play over and over. I understand that in real life there are times when a team will run a play over and over until the other team stops it, but since the CPU doesn't make great adjustments it just isn't realistic. I run and pass out of multiple formations of ace, shotgun, pistol, full house, offset I, I, Power I, and wishbone. I simply do a little bit of everything just to have more fun with the game. When I pass the ball, I never exploit the deep routes. Any vertical routes that I have are always at least my second option, so I have to check down and make a quick decision if I am going to try to pass deep. Normally, with the sliders that I have set up there isn't enough time to let the vertical routes get open anyway.
Right now I'm about out of ideas that won't make the gameplay poor. If you have any other house rules or something that would help me out let me know. The current season that I am I struggle to win most of my games, but still always come out with victories. It is strange because I will play a team like San Diego St. and they will move the ball well against me, but I will do enough to score more points than they do, and then I will play Ohio State and shut them out 20-0.