Get Skyscrapers in SimCity 4

If you have been building a city that has a big population, but no tall buildings, here are a few pointers on helping you get skyscrapers.

Steps

Focus mainly on commercial districts. You will not get any commercial skyscrapers at all unless you have an office population of at least 5,000 workers. Once you reach that milestone, you can build a stock market which attract large buildings.
Make sure your area is desirable enough. A good commercial area will be away from industrial parts of the city and have several plazas nearby, along with a high land value. Also be sure that the commute is okay. This means that there are residential areas nearby and it doesn't take long for Sims to get from their homes to the business area.
Give your city good highway and freeway connections. Freeways are a good choice because they support far more traffic than other roads. It is definitely needed if your city has commuters from other cities. For shorter distances, like just across town, avenues work well also.
Give your city enough power and water. Make sure you have high density zones, because taller buildings cannot develop on low density land plots. You will also need Hi-Tech Industrial zones in your region or city.
Make sure your taxes aren't too high. Low taxes means less income, but more people will come.

Highways, freeways, and avenues can provide better transportation for Sims, therefore generating more demand for offices and large companies, and thus getting tall buildings.
Build commercial areas away from industrial parts of the city.
Make sure your city is desirable enough.
Make sure your zones are high density.
Add more civics and ensure crime is low.
Keep in mind that the required population for skyscrapers is not solely based on your city's population, but also on the population of the region as a whole.
Make sure that every block has a form of mass transit. When your city progresses traffic will be higher therefore skyscrapers won't develop.
Use other transportation options than just roads, try using elevated rail, subways and monorails.

All cities can develop skyscrapers but some cities will need more requirements, such as the larger cities will need more commercial office population.