I'm struggling when I'm under early pressure. I do get my economy up and running quite nicely. If I get past the 11-12 minutes there is no problem (yet^^). But withstanding the first agression seems hard to me. At what time do you start building barracks (I guess building units from the barracks is the most effective defense)?
Normally, I age at 17 villagers and start producing my first barracks units at around 9:00.
Best Answer
General tips
Going to the colonial age with a settler-population of 12 is generally way too low - especially for the British and Germans. 17 is a good number for the British to reach before going to the second age, so nothing to worry about here.
The shipment of two outpost wagons is an exceptionally bad card. Not only is it only worth 500 wood, but you cannot use it for anything other than "staying alive". Compare that card to 700 wood, with which you will build houses (which in your case will grant you settlers as well), build a barracks, build a market and getting the upgrades, and finance the training of longbowmen and pikemen. Compare it even to the 6 longbowmen-shipment (worth 360 food and 240 wood) that gives you soldiers that are ready to fight as soon as the shipment arrives, and are not wasted if your opponent decides to not attack.
If your opponent forces you to send the shipment of two outpost wagons by simply putting early pressure on you, he has essentially accomplished more than one can ask for and is at a clear advantage.
Early aggression is especially effective against new players, because they do not know the tricks and small details that have been discovered over the years of people playing this game. I will go through these below:
Town center-fire
Your town center is an insanely important defensive utility, especially in the early-game. For every settler garrisoned inside, it gets 9 ranged damage. Having 4 settlers inside gives it 36 ranged damage, making it able to kill an enemy musketeer or crossbowman in 4 shots. As soon as the enemy troops get in range of your town center, you should garrison some settlers (4 is a good number) and start hurting them. Do not let the enemy troops roam freely in your base!
Herding
When an animal (e.g. bison, deer) is shot by a settler, it runs away from it and the rest of the herd follows it. This means that you can control the herd to be very close to your town center, and this is important for two reasons. The first reason is to not waste precious villager-seconds walking all the way to the distant animals to gather food. The second, more important reason, is that your settlers are close to the town center and can pop inside quickly both for protection against enemy troops, and to give the town center the ability to fire at enemy troops which we discussed above.
The technique of shooting the herd of animals in the direction of your preference is called "herding". Keep in mind that the herd has a cooldown of 12 seconds. Do not try to herd if 12 seconds haven't passed since the herd last ran a short distance.
Minutemen
Minutemen are incredibly strong units (and cheap ones) that can be trained almost instantly, but can only be sent once. Minutemen are almost never used correctly by new players. Usually new players call their minutemen as soon as they feel a little too much pressure. The enemy can then easily retreat and come back a few seconds later when the minutemen are almost useless (since they only have 1 hp left) and crush you since you wasted 300 precious resources.
The correct way to use minutemen is to use them together with the rest of your army when the troops of your opponent have gone too deep into your base that they no longer can retreat, and therefore will get annihilated by you. Obviously your enemy might be fully aware of this and not fall into this "trap", in which case you have somewhat managed to hold him off and the battle from here is especially easy as the British, since your archers have a very long range of fire, and you also have an outpost from when you reached the colonial age.
British-specific tips
Choosing the correct politician
As the British you have four options:
4 cows:
This option is utterly useless. Never choose this.
2 settlers:
This option is only useful if you know that there will be no battles in the near future at all. Do not choose this unless you are playing no-rush (also called treaty).
Outpost wagon and 200 coin:
The outpost is useful against early aggression for obvious reasons, and even if you are not getting rushed, you can still use the outpost to secure resources that are somewhat distant.
The 200 coin is incredibly useful. Hunting dogs and steel traps (the market-upgrades), musketeers, and of course the lovely minutmen all cost coin.
500 food:
Food is the resource that gathers the fastest (even faster when you have researched hunting dogs), so 500 food is not as incredible as it seems. If you are getting rushed, the outpost and 200 coin are very useful as stated above, and if you aren't getting rushed, the market upgrades and the utility from the outpost are worth more than the short-term boost in food (which you don't need since you don't need military units anyway).
If the British had the 400 wood-option, it would be lovely, but they don't. The second best option is the outpost and 200 coin, so go for that one.
Good placement of houses
Whenever the British civilization builds a house, they get a settler as well. But since there is a limit on the amount of houses, it is not possible to max out on settlers by simply flooding your base with houses (which would be OP). However, whenever a house is destroyed you can rebuild it and gain a settler that way - so in general the enemy of the British would not like to destroy their houses, and even if they did it would be hard since the British houses have much more hitpoints.
Keeping this in mind, we realise that instead of having to build our houses in protectable areas in our base, we can build them as a wall in front of our base together with our barracks and outpost and place our longbowmen behind that wall. This forces the enemy troops to walk around a lot of buildings to be able to reach the longbowmen, absorbing fire from longbowmen, the outpost, and the town center in the meantime.
Wrapping up
Having settlers close to your town center ready to pop inside in any moment, a wall of buildings with longbowmen standing behind, an outpost and a town center ruthlessly shooting down the enemy troops, and the possibility to send minutemen and ship 6 longbowmen from your home city should be able to hold off any early attack.
By no means it an easy task keeping track of all this at the same time as doing everything else you are supposed to do. Try to master one thing at a time so you do not confuse yourself trying to implement all these things in your game-play at the same time.