This guide discusses different early strategies when building the first worker or settler, from the first city. (We focus on the first one only to avoid the hot issue of whether w-w-s or w-s-w or s-w-w or whatever is the best sequence
)
Assumptions:
a)standard map,
b)normal speed,
c)the first city has access to at least 1 square with 3 food, and at least another square with 3 productions (food + hammer).
d)bronze working is researched when slavery is needed for certain strategies. (Note: for a worker at turn 15, only possible at lower difficulties and/or with mining as starting tech)
e)anarchy turn for revolution is neglected for simplicity. (Assume the revolution eventually takes place, then in most cases the loss of one turn will happen sooner or later. Major differences are limited to the rare tight situations when you beat/lose to another civ by one turn for a key tech or wonder.)
f)the extra commerce from working a bigger sized city is not discussed.
1. worker
1a) build worker from turn 1:
1a1) takes 15 turns to finish (60 hammers / 4 per turn), zero overflow
1b) build worker after reaching size 2:
1b1) takes 8 turns to size 2, 2 extra food, 8 hammers for a warrior
1b2) start building worker. Takes 6 turns to get 30 hammers (5 per turn), change to slavery and whip
1b3) worker accomplished after 15 turns with 4 overflow
1be) total gain over 1a: 2 food, 12 hammers for a total of 14 productions
Rationale:
Each whip from a size 2 city converts 22 food to 30 shield = gains 8 productions. Subsequent whipping yields less (size 3: 24 food to 30 shield = 6 gains, etc.)
1b) whipped once and stayed in size 2 for 6 turns, hence the total gain was 8+6=14 productions.
2. settler
2a) build settler from turn 1:
2a1) takes 25 turns to finish (100 hammers / 4 per turn), zero overflow
2b) build settler after reaching size 2:
2b1) takes 8 turns to size 2, 2 extra food, 8 hammers for a warrior
2b2) start building settler. Takes 14 turns to get 70 hammers (5 per turn), change to slavery and whip
2b3) settler accomplished after 23 turns with 4 overflow
2be) total gain over 2a: 2 food, 12 hammers for a total of 14 productions (minus loss of production for the halted warrior).
2c) build settler after reaching size 4 (this requires 3 food-abundant squares and a forest):
2c1) takes 8 turns to size 2, 2 extra food, 8 hammers for a warrior
2c2) takes 6 turns to size 3, 2 extra food, 14 hammers for a warrior
2c3) takes 5 turns to size 4, 1 extra food, 1 warrior built and 4 towards the second warrior
2c4) start building settler. Takes 6 turns to accumulate 42 hammers, change to slavory and whip
2c5) accomplished after 26 turns with 7 overflow
2ce) total gain over 2a: size 2, 1 food, one warrior, 11 hammers for a total of 27 productions, but it takes an extra turn.
Rationale:
Each whip from a size 2 city converts 22 food to 30 shield = gains 8 productions. Subsequent whipping yields less (size 3: 24 food to 30 shield = 6 gains, size 4: 26 food for 30 shield = 4 gains, etc.)
2b) whipped once and stayed in size 2 for 14 turns, hence the total gain was 8+14=22 productions (8 of which translated to finishing two turns earlier).
2c) whipped once at size 4 and stayed in size 2 to 4 for various number of turns, hence the total gain was (6+4)+6+2*5+6*3=44 productions. An extra turn gives 5, makes a total of 49 -- 22 of which translates to an extra population.
Conclusion: If you have at least 1 food abundant square, then building a worker/settler from turn 1 is not the best strategy -- unless you cannot get bronze working in time.

Assumptions:
a)standard map,
b)normal speed,
c)the first city has access to at least 1 square with 3 food, and at least another square with 3 productions (food + hammer).
d)bronze working is researched when slavery is needed for certain strategies. (Note: for a worker at turn 15, only possible at lower difficulties and/or with mining as starting tech)
e)anarchy turn for revolution is neglected for simplicity. (Assume the revolution eventually takes place, then in most cases the loss of one turn will happen sooner or later. Major differences are limited to the rare tight situations when you beat/lose to another civ by one turn for a key tech or wonder.)
f)the extra commerce from working a bigger sized city is not discussed.
1. worker
1a) build worker from turn 1:
1a1) takes 15 turns to finish (60 hammers / 4 per turn), zero overflow
1b) build worker after reaching size 2:
1b1) takes 8 turns to size 2, 2 extra food, 8 hammers for a warrior
1b2) start building worker. Takes 6 turns to get 30 hammers (5 per turn), change to slavery and whip
1b3) worker accomplished after 15 turns with 4 overflow
1be) total gain over 1a: 2 food, 12 hammers for a total of 14 productions
Rationale:
Each whip from a size 2 city converts 22 food to 30 shield = gains 8 productions. Subsequent whipping yields less (size 3: 24 food to 30 shield = 6 gains, etc.)
1b) whipped once and stayed in size 2 for 6 turns, hence the total gain was 8+6=14 productions.
2. settler
2a) build settler from turn 1:
2a1) takes 25 turns to finish (100 hammers / 4 per turn), zero overflow
2b) build settler after reaching size 2:
2b1) takes 8 turns to size 2, 2 extra food, 8 hammers for a warrior
2b2) start building settler. Takes 14 turns to get 70 hammers (5 per turn), change to slavery and whip
2b3) settler accomplished after 23 turns with 4 overflow
2be) total gain over 2a: 2 food, 12 hammers for a total of 14 productions (minus loss of production for the halted warrior).
2c) build settler after reaching size 4 (this requires 3 food-abundant squares and a forest):
2c1) takes 8 turns to size 2, 2 extra food, 8 hammers for a warrior
2c2) takes 6 turns to size 3, 2 extra food, 14 hammers for a warrior
2c3) takes 5 turns to size 4, 1 extra food, 1 warrior built and 4 towards the second warrior
2c4) start building settler. Takes 6 turns to accumulate 42 hammers, change to slavory and whip
2c5) accomplished after 26 turns with 7 overflow
2ce) total gain over 2a: size 2, 1 food, one warrior, 11 hammers for a total of 27 productions, but it takes an extra turn.
Rationale:
Each whip from a size 2 city converts 22 food to 30 shield = gains 8 productions. Subsequent whipping yields less (size 3: 24 food to 30 shield = 6 gains, size 4: 26 food for 30 shield = 4 gains, etc.)
2b) whipped once and stayed in size 2 for 14 turns, hence the total gain was 8+14=22 productions (8 of which translated to finishing two turns earlier).
2c) whipped once at size 4 and stayed in size 2 to 4 for various number of turns, hence the total gain was (6+4)+6+2*5+6*3=44 productions. An extra turn gives 5, makes a total of 49 -- 22 of which translates to an extra population.
Conclusion: If you have at least 1 food abundant square, then building a worker/settler from turn 1 is not the best strategy -- unless you cannot get bronze working in time.