So I'm nearing on lvl 20 atm and now maps  are starting to get a bit harder.
Almost all the time the an enemy will send a sizable force at me a few mins in.
 
Some maps are not a problem you can choke off with some walls to help out your dudes.
Not so much on open maps. Another problem is that forces are usually so large that the help from the town centre and/or towers is almost insignificant.
I'm usually pumping out more peasants at the start and quickly teching to age 2. As soon as age 2 hits starting to pump out units while simultaneously continuing production/tech.
So by the time the enemy force comes I usually have a sizable one of my own.
 
However it's not enought frequently and 3 times in a row now I had to resort to consumables in order to give myself an army/defence boost.
Which seems not a goood long term strategy.
 
Anyone else esxperiencing something similar at higher levels?
I know Brad was in the chat yesterday having the same problem too, but at the time I have not yet come across this myself.

The missions do become tougher to be sure, if you are not a F2P member I would recommend using advisor cards and teching up the tree to your strengths.  (For example, I have premium greek and teched up infantry which seems to be working really well for the quests) 
 
I know this doesn't offer much if any help but without knowing the exact mission I cannot really help you with it :/ sorry. 

I do find that they rush you with forces around level 20 that you are not capable of fighting right away. However, only once has this been to the total downfall of my village. My strategy? Walls, walls and more walls are your friend at this point. If you can get a defensive perimeter going, then you can actually set your workers to repair the wall faster then they can damage it, but they might use archers to take down your workers.

While they're attacking the walls, or even if they manage to break through and go after your smaller buildings like houses, guard towers will chip away at them slowly. You may lose a few towers and need to recall all villagers inside your town centre, but even then, your town centre has around 8000 hit points, so it should take out any damaged units. As long as you have villagers left, it doen't matter how much of your base they take out. When they've gone, rush the stone mines, rush them towers out. I personally found an advisor that gave 20% more damage to towers, so that sure helped. Eventually, each time they attack, they manage to do less and less damage until eventually you have enough defense going that you only need to focus on repairing. Eight towers may seem a bit much, but it sure as hell means they're constantly under attack from all directions.

That's what I do anyway, I barely put any tech points into infantry at all, so I don't know how effective spamming a bunch of units might be. My points went into walls, towers and elephants. Elephants are killing machines, if you're Egyptian, and quite ridiculously overpowered if the chat is to be believed.

Edit: Oh, and I find usually on maps that rush you with huge forces, they're usually comprised of elite units, in which case trying to match them with tech 2 infantry doesn't end well. One elite axemen will take out at least five of your axemen.

I had a problem similar to this last night at a lower level quest (around lvl 7, I believe) in which they kept sending about 6-10 guys my way ever few minutes or so and they were even able to get in and kill about 90% of my villagers at one point. At least, I'll know to watch for it in the future and get those watch towers/walls up before I make my move outward.

Yea I have invested a bit in good infantry so my anti infantry dudes can scythe through the enemies inf, but it was still not enough :(
Ging toe to toe with elites of the same type is just a no win scenario.
 
@DeeGee: 
I'm thinking you're right walls seem to have saved by bacon in a couple of cases, and the trouble was always when you are out in the open so I did not build walls.
From now on I'll be putting down walls even when there are no chokes.
There is sadly no elephant equivalent for Greeks in the early ages.
 
Hitting level 20 is a bit overwhelming, too much stuff opens up at once. :)
Any greeks here who found good routes in the tech tree to take?

@DeeGee: These are awesome tips, thanks!

I just had a slug fest trying to solo Egyptian Alliance. (Ironically, the Egyptian Allies aren't good for much aside from sitting pretty.)

I think at this point I'll start getting used to building walls to keep my enemies at bay, too.

Interesting advice.

I'll have to start upgrading my units, since I've gone for the economy upgrades so far.

To the comments about elephants, I haven't found them participially useful. When I have gone against them, camel riders seem to take care of them. Spear men however will get ripped to shreds. Its the splash damage.

@sirdesmond said:

I had a problem similar to this last night at a lower level quest (around lvl 7, I believe) in which they kept sending about 6-10 guys my way ever few minutes or so and they were even able to get in and kill about 90% of my villagers at one point. At least, I'll know to watch for it in the future and get those watch towers/walls up before I make my move outward.

Yeah, I noticed a spike in difficulty around that level too, mainly because you don't have access to a lot of the more helpful units yet.

I just hit 21 and have been having this too. I like it, I wish the AI kept up the pressure though. I've found the game too easy until this point. My strategy was just to tech to age 3 asap and spam Hoplites and roll across the map. If I do that now, I will die unless I use consumables. 
 
Now my strategy is to balance units with teching early on, which is actually more fun. I might try playing defensively with walls and towers too and see how that goes.

Yea after the pre 20 hump it's now again become managable.
The AI still floods me with dudes at some point, but having respeced my tech tree I can hold off the initial rush off more eaily now.
But now trying to clear out AI emplacements without siege usually ends witha lot of losses so I'm usually sitting in my base until siege comes out.

There is however an alternative stategy of peasant rushing that people have been using in PvP as of late that also works on AI on maps where the AI is not already build up.

My strategy is usually to not close off the entire perimeter but rather leave a hole open. This means the AI will be 95% sure to use this entry point, and this allows you to focus your force in a specific spot.

@Vodun: This was the way to work it in Age of Empires 1 and I guess the strat still works. It's also fun to add a small maze at the gap so the AI gets all muddled up. I was having issues when I headed into Nubia. The Golden Punchbowl kicked my ass a number of times when the AI rushed me with 3 massive armies at once all while I had a 15 minute timer on collecting 5000 gold. I had to drop a consumable and roll their 3 town halls just to make it.

One thing I've noticed, and this might be completely incorrect with such little data, is if I scout around fully - reveal the entire map level of scouting - the AI will not do its ridiculous rushes. This could be an issue with how the server is "playing against you" differently based on what you can and can't see or what's been revealed. It seems like if I leave the map in the dark for any extended amount of time in the game, then I move out into it there is a full blown colony right up to that edge and waves of swarms. 
 
I've only tried it on a few missions where I kept getting rushed with a ridiculous amount of troops only a few minutes in, then spam scouted and had no rush.

Play really defensively or really aggressively. 
 
Aggressively - build units really fast. Before teching up. And keep building a few as you tech up. Use the army to defend yourself. Alternatively, in some missions, you can rush the AI and beat it. That stops working at level 30 though. 
 
Defensively - Walls, towers, fortresses and archers. Use these to defend early on while you tech up.