actually, this is warlord!!
hi, ksim, i had a look at your savegame. i was a little bit dissappointed, because a couple of things were not as you depicted the situation.
first of all, it's not a monarch game but it's on warlord. the ai is heavily handicapped, and that's bad news in regard to trading techs. the good thing is: the ai is not much more advanced than us!

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Second, you toggled off some of the victory conditions. the game can only be won by conquest or space race. for a victory point scoring you have to conquest more victory point locations. these are the capitals of the other civs, which means conquest, too.
seems to be hard to win this game. historiographic victory seems the best solution.
here are my play along notes i kept:
it's turn 234, 1190AD, you haven't met anyone yet, you still have got 2 unconnected cities on your island, your cities are producing wealth!
you have researched Iron Working (who are you going to invade?), Mysticism, Polytheism, but no Map Making though we are probably on a huge archipelago map and you've already got Writing.
Your workers are building irrigation on grasslands in despotism. that means you get nothing out of that - irrigation bonus is negated under despotism, every resource above 2 produces one less.
Grassland produces 2 food;
Irrigation produces 1 additional food;
Irrigated grassland produces 3 food;
Minus 1 because of he despotism penalty;
----------------------------------------
you still get 2 food
I jump into the game. I can win by victory points, conquest (duh!) or space race (Duuuuuuh!!).
Philosophy will be discovered in two turns, then i stop research completely to earn some money for trading.
I want to improve all of our lands as fast as possible, therefore cities with food surplus will produce workers. workers are building mines and roads, replacing the irrigation where neccessary.
I need trading partners so exploration will be the second major directive. cities on coasts will produce curraghs. i can see a border to our west, and another island coastline to our east.
i want to reach those as soon as possible under any costs, that includes suicide curraghs (curraghs are not supposed to end their turns on sea or ocean, but they have a certain chance to survive; suiside galleys/curraghs gamble on this risk in order to discover new worlds).
2 curraghs are heading west, one sinks, one survives, contact to Sumerians.
surprisingly, Sumerians are not much better off than we are. they only have 3 techs to sell: maths, horseback riding, monarchy. we can put the newly discovered philosophy on the table. they would trade horseback riding for philosophy but hbr is preety useless for us so far. i decide to buy maths for philosophy + 106g + 2gpt.
on the island to the east there are the Indians. I discover them in 1280. they have only 3 cities because they are on a very small island and they have no techs to trade. i sell them Writing for all of their gold (63g).
besides, i started a prebuild in one of the coastal cities. the city builds a palace for now. as soon as we get map making it should switch to the great lighthouse. when we get the lighthouse, our ships will get a additional movement point and will travel across sea tiles without the risk of sinking. this is veeeeery nice on an islands' map.
my summary:
good things in your game so far:
- you've settled almost all of the island. i tried to squeeze some more cities in to make more money and get the free unit support.
no so good things:
- you haven't explored anything.
- you didn't focus enough on what is immediately neccessary. you're on a lonesome island, so you need ships, no swordsmen.
maybe a little much info. here's the save from 1300AD.
Tokugawa1300AD.SAV