SimCity DS

That depends on the density of the zone you are building. It's best to raise tax to 8% and use light zones at first, then, when you get around 20-30 thousand population, begin building medium zones. Keep in mind you still may need a loan, but if you do, the 10k works best.

maybe you are over bearing your city with expenses that are not needed yet, just remember not to build to many civic buildings too early e.g try to refrain from building a university until you have a pop of around 15 thousand or until u see the city's growth slows or stunted mainly in the commercial and industrial areas. if growth stops in the res areas that means that something else is wrong e.g high taxes are lack of qual of life among a few other things another thing is not to build railways and stations to early start building them around 25 thousand pop. something else that i found my self falling in to was the fear to demolish zones to make the city better my guess is your doing the same thing and that does more harm than good a poorly zoned area will chase away citizens even if you have a better zoned area, so all you will have to do is find the fault in that zone demolish it and remodel the zoning in that area so here's a recap:
Step 1)don't over expense you're city.
Step 2)watch city growth closely. {displayed at the bottom left of the screen the R.C.I bar}
Step 3)build railways only when pop is high enough to support it.
Step 4)DEMOLISH!!! if a zone looks like crap that means it's crap and time's not going to change that if it's broke FIX IT!!!
Step 5)have a bit of patients when you realize that the city is having a good positive income let time pass bit and let the money come in {i know, i know i did not mention this earlier}
Just follow these steps and you'll have no problem, you may not even need to take out a loan or if you do you'll have that loan repayed in no time. EvilJackCarver has a good point too you should follow that as well.