I know someone has mentioned killing off the other European colonies very early, but I have a little tweak (exploit)
I killed off all 3 of the other colonies mid game. Their kings kept sending more colonists. I kept capturing their new colonists (getting 1 to 3 extra pioneers every other turn or so). Here is how it worked. Defeat last colony & all colonists. Kill caravel with SoL or Privateer. Next turn, new caravel arrives from Europe with the civ's starting colonists (pioneer & soldier). Wait for them to land and make new colony with soldier. Invade. Capture/Raze colony. Capture helpless pioneer. Take said pioneer to your production city. Give him some guns. I've done this @ 10 times now in my current game. It has really helped build my military quickly (along with a food city popping new citizens about every 7-8 turns)
I killed off all 3 of the other colonies mid game. Their kings kept sending more colonists. I kept capturing their new colonists (getting 1 to 3 extra pioneers every other turn or so). Here is how it worked. Defeat last colony & all colonists. Kill caravel with SoL or Privateer. Next turn, new caravel arrives from Europe with the civ's starting colonists (pioneer & soldier). Wait for them to land and make new colony with soldier. Invade. Capture/Raze colony. Capture helpless pioneer. Take said pioneer to your production city. Give him some guns. I've done this @ 10 times now in my current game. It has really helped build my military quickly (along with a food city popping new citizens about every 7-8 turns)