Airborne races have a huge initial advantage in
exploration and expansion because their settlers
can fly over water. Their inability to exploit
barbarian villages is a small price to pay.
In the fantasy scenarios, it pays to seize control
of the entrances to the underworld. There are
relatively few of them, and they are easy to fortify
if you move quickly; the rich underworld resources
can be all yours.
In the extended basic game, remember to be prepared
for a long war once the colony ships are launched.