Fresh starts are the best starts! It really depends on how you want to play, but I have my old favorites I like to goof around with in every single save. I have certain townie sims I like to give makeovers to because I love seeing them at their best. I also try to explore sims that tend to get ignored and see if there is something fun to do with them. When I start a new save, I usually turn aging off. I try to populate as many residences as I can in Willowbrook, Oasis Springs, and San Myshuno. As I'm doing makeovers and populating them, I'll usually get them started on their careers and skills which helps drive them to show up at different places. I also get my modes tuned in for the new game because defaults are usually a bit too strong. Lastly, I do use Neighborhood stories but I make sure to turn off a lot of the stronger options. I don't need couples adopting 6 dogs, quitting jobs, or randomly moving out like they tend to do if you turn on Neighborhood stories as is.
Also make sure to check out some Custom Content. I mix it in with the game outfits to give some flare to characters. I avoid sliders though because they apply to townies randomly and I get some really extreme-looking sims which I don't like.