hmmm, it's really kind of hard to say what you might or might not be doing wrong -- or even if what you are doing is wrong, really, as there isn't any right or wrong way to play this. At least I don't think there is anyway.

Try to have them pick up the collectibles. You get five dollars for every common collectible that they sell and more for the uncommon and the rare ones. That can actually add up fairly quickly.

Don't buy them too much food, even if they send you an email asking for "different" kinds of food it doesn't mean they really need it. You can click on the fridge and it will tell you how much food is available. Mine will send me emails asking for more food and when I check the fridge it'll say they have 3,690 (just an example, but A LOT, lol!) and I'll know that I don't need to buy more.

Don't buy stuff as soon as you can afford it. Wait and let the money pile up. The more money that is in the bank, the more you get in "interest" so you actually make more money by letting it pile up. When I first start a new family out, I just buy the cheapest food (for most of the 1st generation of that family) and the only "extra" I buy is the radio. I'll buy medicine if they need it, of course, and even buy the doctor's consult if one of them keeps getting sick a lot; but otherwise, I don't buy much during the 1st generation so that the money starts piling up really well. As I said, since you make 10% in interest alone on the money that's being saved, the more you have in the bank, the more you get each day in interest as well. Be skimpy with the first one or two generations and you'll be amazed at how much money you can end up with by the second, third and so on generations.

Hope that helps, good luck!