Colonization: Fast growth initiatives, Nr 1
In the first 100 turns (before 1600), you need to build cities frantically.
Reason 1: There is a game-wide limit of about 42 cities or so. The faster you get close to 40 cities, the fewer cities your opponents will be able to build, and the less they'll be able to stifle your expansion.
The max number of colonies you'll be able to base could be between 30 and 40, with 34-36 being common, and depends largely on how fast you move, and how fast other civs are building cities.
Reason 2: Any colonist is put to better use starting a new city than working in an existing city. New cities get one square (base square) free, so one extra production square for the nation.
Reason 3: Each new city generates one free bell and one free cross.
Your first 36 or so colonists should go to build 36 colonies, one per town, this is the single most efficient use for a colonist early in the game.
So consider yourself in a race: a race against your opponents, and a race against time, to build cities. You need to have such a sense of urgency about founding new colonies, that you may need to base towns even in unfavorable locations.
Fortunately, the game allows dismantling a colony, so "Temporary" cities are possible, and often are a must.
A temp city is a city you build just to reach the max number of colonies faster, or to occupy a spot before your opponent does. Once you max out, you'll be able to change colony positions. You'll do that by taking all settlers out of the temp colony, and immediately (***IN THE SAME TURN***) base a permanent colony in a better location, were you already have a settler waiting to receive the build order. If you wait one turn, an opponent will build a city for the slot that has been freed up.
You must know from the start which cities are permanent, and which are temps. You will not build hard improvements in temp towns. Movable goods and wagons only. You will send wagons/ships to evacuate all goods from a temp town before dismantling it (provided you like efficiency)
To retain the ability to dismantle colonies, you should NOT hire Sieur de La Salle in your Congress, until you've got your urban planning down to final shape. Not that a temp town should ever need to grow to 3 citizens or beyond, but it will just keep you from accidentally anchoring a city you never intended to keep, by some benign, and inadvertent shifting of worker jobs inside a town.