It happens (a lot to me
) My normal big mistake is with the portraits but I had that down. I had some sweet properties purchased and fully upgraded (hospital & Art Gallery in Union Cove) Tons of cash on hand.
It was on gen 1.5 - Gen 2 was a late teenager, on the verge of young adult (already had her spouse lined up and her logic skill to lvl 9)
Gen 1 founder spent a bit too much time on his ltw (golden tongue/golden fingers) and earning money with his guitar and didn't gather enough special seeds to really get the money trees running. He didn't go a day long, deathflower used at 92 (90?) days = fail. It was a bit of a gamble that he might have a few days to max out his gardening career... his steak plants were planted to finish up the omni plant chain, the crop was going to be excellent, and he was going to be able to start growing books in about 5 days.
I believe that the first generation has to be the hardest in this challenge. Once you're set with cash flow the purchase/upgrade is easy, once you're set with the house growing up isn't difficult (easy wish points buying new cribs/potties/highchairs etc). You need the garden & death fish in place for gen1 anyway, easy to keep going.
This was try 7 iirc. I made several attempts with painters & sculpters as the first gen, one with a cook as first gen, one with a writer (that was a good story, the whole thing was a work of fiction / dream in her mind.... she fell asleep at the keyboard in the library) This guy I started out supermaxing guitar and then switched part way through to gardening - he had it supermaxed and it was his career, but I didn't pay enough attention to his age before putting the career drive on -- was spending too much time on making friends & playing guitar for tips.
Next attempt: founder is going to be a gardener again but I'm going to pay a bit more attention to the career.
I don't know if it is a strategy mistake or not, but I've been flagging fishing as a free-for-all skill. The sims all seem to enjoy it and I think in later generations I'll want to be able to park them fishing rather than jumping on the trampoline or playing in the sprinklers. I do know that several of those who have completed the challenge have used fishing as a skill for at least one of the family...*shrug*