um....get photo references. Best resources anyone can ask for.
When it comes to drawing architechy stuff it's best to use a straight edge of some kind. Preferably rulers (traditionally).
On comp, many people have their own ways. Pin tool, line tool, and even Freehandedly draw them using your own sights for judgement. However, you really should just roughly sketch the picture. Use 1-2 or 3 point perspective to help you with the rough as much as you can and then once you're done you can use all the tools you want to get it into a finishing state.
If you don't know how to use perspective, go do a search via google or something of the likes and read about them. It's really not that hard. The hard part is putting it into work and your own understanding of how to use them.
Good luck na.