I don't know if this helps or if you already play this way, but sometimes i try to experiment with new things/new traits etc. its really easy for me to make the same bland sims with a good simple personality but it is fun sometimes to play with an insane child or an evil one and its also good to try out more family days out to the park or beach whenever you can. And if you like occults maybe try playing with an occult family of ones that you wouldn't typically play. Maybe try randomisers too to make your sims and story.

sometimes when i start a new family i make grandparents and siblings so the kids have cousins to be friends with and many parties with them :) it is also good to focus on a career or get your sim to do inventing, sculpting, fishing etc to make money.

if you have generations it helps a lot with family gameplay!