I always bump the frequency and richness of ores usually around 25-50%. Making it too high, i feel removes the push to expand. Too low and i can't get resources without it being a slog everytime. I also find it enjoyable to turn up the minimum time between attacks by just a few minutes. It gives me time to try to make something nicer than it would be otherwise.

But that's just how I like to play. One thing I love about Factorio is they put those options in there because no matter what your preferences are, that's how the game is supposed to be played.

That said, it can also be fun to do a vanilla run or even just skip changing a single setting you'd usually alter. It's amazing how much a single setting can change the way you approach a play through.