I feel it'd be quite entertaining to know how others' Sims rose to success in the small-business career.

I once got a level ten business for Jason Larson selling...wait for it...

I'm probably the only one here that will understand this reference but

BRASON!

the irony of the owner's name is too much to handle

When OFB released and I installed it (long time ago) I had one (and only one) business what I got to top rank. She was selling flowers... These what you put into flowerbeds when you decorate your yard. Later when I made any townie playable I found lots of flowers in their inventory.

Most of my business for my new hood are shown on my thread here: https://www.modthesims.info/showthread.php?t=561271

All of my attempts at a successful business have failed. Probably because my Sims had careers to attend to at day.

You can juggle a job with a business, but it certainly is harder. Putting out the Simlogical institution sign while you focus some days on the business can be helpful.
The main thing with a new business is 'cheap prices= happy customers and happy customers= more stars.'

Yeah, my business's are not about money. It's about stars. Get that ten, hire a manager, then worry about money

If you get the stars the money takes care of itself, well unless you have hired a hoard of sims to run it and forgot to raise the prices.

My most successful business (level 4 - I'm more interested in giving Sims interesting and personality-relevant businesses that don't bankrupt them than creating the next business empire) was a Sim selling bowling alleys on the front lawn. Some Sims bought as many as three lanes on the same trip, which naturally made the owner quite rich, as well as justifying his lifelong obsession with games.

Another successful, if offbeat, business, sold piles of dirty laundry, lumps of mown grass, and other items that nobody needed but everyone seemed to want.

Adult Ivy Copur owns Ad Astra, a telescope store. Since telescopes start at about §500, she makes a tidy profit. Among her items for sale is garotinho's Teslescopio dos Verdinhos, which can be set for guaranteed abduction. I've made it into a lottery of sorts, in that any adult male Sim who winds up with this telescope in his inventory has to be abducted. Ivy is doing booming business, so while playing the store I often don't see who is buying the green telescope. I can't wait for my former mascot to get abducted next round!