The reputation you have with the faction of a country effects how much support you can get in that country. If you have more units than you can actually support, then they are held in reserve when you enter RTS. As soon as you free up more support, they can be brought into battle instantly, and without cost, from the appropriate factory.
Taking over or building recruitment citadels will increase your support cap.
Dragon Commander: The Complete GuideYou can use the Numpad + and - keys to increase or decrease the game speed.
I like the mountain dragon. Rejuvenation and Blood Leech help a lot with survival, and Acid Blaze is great to switch to when your regular attack gets close to overheating (and I learn Breaching Fire, Devastation and Scales of Steel when available; Soar is good early in the game, but is expendable once you start picking up some of the higher level skills).
It helps to have a couple shamans at your base (or somewhere handy behind the front lines) that you can retreat back to, for faster healing.
