I started in the beginning of February. 2 months ago I got all land expansions plus sea expansions, plus last month I got all aspirations. I now have nothing to use my millions of money for anymore.
What made me gain money fast was to not do any of the quests. Instead I'd put characters on 8 and 12 hour tasks all the time and I used pink and blue house farms.
I don't get why house farms are considered a bad thing though. I love to see a lot of houses in my town make up an entire neighborhood. I make sure to have plenty of space inbetween houses so that cars could drive and I have lamp posts dividing the houses. I go for a realistic look so having lots of houses looks natural for all the inhabitants.