I've never managed to make a profit in this game :/
I did. It's not that hard. The thing is, you just keep buying/funding things only to the bare minimum, and expand the zones as the RCI demands. The latter is very important - if you're not making enough money to cover the expenses, do not raise taxes, do not cut expenses to below what is needed - zone out more areas instead.
Oh, and don't try to force the development. When I was a kid, as I was playing I tried to go from nothing at all to a service-based economy. Start out from an agricultural community with some shops, add some industry to the area, then as you get a proper educational system in place you can slowly upgrade to higher density and more commerce-heavy economy.