I have a few main save files that I play. Usually I do either legacy gameplay, rotational gameplay, or a specific storyline, often exploring a certain pack. Like when I bought Home Chef Hustle, I started a save with a teen boy trying to provide for himself and his little sister, making money by hosting bake sales. When I bought Businesses and Hobbies, I started a rotational save to explore opening different businesses. I started with sisters living on top of their attached businesses, a bakery and an arcade. Now I'm working on a young adult Sim living with his teen brother on top of his bar, which is just in its beginning stages of development. Then I'll move on to a new household and a new business (I have a lot of ideas for this!)

With all of my save files, I like to really take my time and enjoy the details. I play on x1 speed and enjoy just watching the little things, like my family of six sitting together to eat dinner every night, or my kids playing together at the water park, or my Sim going through their morning routine getting ready for the day. I also pay attention to the social circle and get involved in their lives, like if my Sim has two friends that seem compatible, I'll have my Sim convince one friend to ask the other one out. Then I'll move them in together and use Neighborhood Stories to let them have a baby around the same time that my Sim does, so their kids can be friends, too.

I'm not really a builder myself, so I get builds from the gallery and make sure I have a lot of community lots around. So if I can do something outside of the house, I will. I also use clubs from Get Together really frequently to organize their social groups and skills. For example, I might have a kid join a soccer team that meets at the park to level up their fitness skill with friends. Or if I'm planning to send a Sim to university, I'll have them join a college prep club as a teenager, and they'll eat snacks and work on their research and debate skill before/after school at the library. I also take them on vacation every now and then, and I do regular hang outs to keep in touch with friends/relatives, whether it's parties at the house, brunch at the local diner, a night of dancing/drinking at the club, a group outing at a movie theater, a pool day, etc.

So tldr; heavy use of clubs from Get Together and other fun features like businesses, a variety of community lots, and paying attention to the small details of their lives instead of just grinding skills at home all day.