Here's a good tip on learning how to beat/match the AI.
Play against one at a desired difficulty, and watch how they work (record and watch and re-watch each replay, and how they work). After I did that, and adapted their technique, I was able to quickly catch up with them in my own game. However, in due time, I noticed they get really damn dependent on villagers to the point it almost turns inefficient, and a viable tactic that once you have a strong enough military force, bleed their villager count dry while obliterating their economic buildings (and replacing them with your own, or at least a wall-cage (palisade being the cheapest) closing the resource off). However, be wary of their counter-attacks, and be sure to counter-counter-attack, or at least make the villager wipeout quick, numerous in killing, and cheap to pull off (at least specializing in villager execution). A few scout units would do nicely, not only to find the economic buildings, but a nice small cheap death squad can slow down their (military) food usage, and making their farms kick the bucket can also severely slow them down; and their constant attempts at replenishing their buildings and villagers will siphon out their wood and food supply rather quickly, which if I recall correctly, is the lifeblood to a strong military.
But yeah, TL;DR: having a rather insane amount of villagers rock, just watch how the computer handles things, and use it as a course of playing like an AI, with additional human common sense.
It also doesn't hurt to dedicate 2-4 villagers to work on 2-4 buildings at the same time 1 each (or all 4 on 1; either way, they'll all be done in the same window of time). I think I remember making an excel spreadsheet that also calculated the rates of production dependent on how many villagers were assigned each building. Best advice, for the fastest and most efficient construction, 4-6 villagers per building tops, and especially with the crane researched, any building can be finished within 16-32 seconds tops, besides the monument which will take 5-10 minutes tops regardless (though 8-12 villagers +crane are advised best for that project to get such times). Of course, the information I used was based on a FAQ I came across where someone already went through the tedious process of counting the seconds of work and estimating the efficiency outputs by adding another villager. I think my spreadsheet also involved, where units are especially concerned (but also applied to buildings if mass-producing units), a resource calculator to give you a total price for (many of) something.
Always a good strategy:
When starting, have 2 villagers dedicated to each task (2 build houses (to expand housing, unless Huns), 2 forage/shepherd, etc.); and when having sheep collected, herd them into your town center and assign every new villager made to work on extracting them, and your food count will skyrocket, thus meaning more villagers. A dock won't hurt either if possible; when food gathering is done for, then farm and place all resource collection buildings point-blank and place all harvesting units to each individual tile. After a good enough while, just leave farming to your fishing ships, and dedicate your other villagers to about 4 farms tops, and the remainder to either collect construction materials or build an outpost in your opponent's blind spot. Provided you did everything right, you should be able to keep up with the AI, and possibly have a blockade force keeping your clockwork town running like a well oiled machine.
In due time, at least how things go out by the time I'm ready to invade, I should have at least 3 castles pumping out units and serving as a great wall of defense, guarded by their castle units and cavalry, and a wave or 2 of battering rams prepared to raise hell on the defense perimeters of the enemy and castles escorted by castle units and cavalry. Hopefully within the next 15-30 mins. they'll fall like a house of cards.