So Im playing as Wu for a while, making no advances against Wei's massive numbers of troops who constantly attack my border cities or bolster their own cities' defenses. Its pretty difficult to attack them, even after defending.
Besides, I have taken over the central plains 100 times, so I was thinking about something new I could do. Thats when I said to myself, hell, the Wu Navy is unrivaled and cannot meet with defeat against any of Wei's miserably land dependent officers.
So heres what I did:
I sent Lu Jing with 55,000 to seize every port in the country, which means I went up through the Chang Jiang, where Jian Ye/Mo Ling is, up through Bei Hei, taking the ports there, and continuing on through Guan Du and Bai Ma, all the way up to He Dong. I did not encounter much Wei resistance because they cannot hope to match Wu's navy.
So right now I control every port in the country, but I have not taken any cities beyond the Chang Jiang besides Jiang Xia.
As outlets to draft more men, I took Shang Dang and Bei Hai with modest numbers; just enough to defend them and help replenish the ports along Wei's cities, each of which I have garrisoned about 10,000 men, depending on the strength of the nearest city.
The strat has been really effective since the central plains are essentially cut off from the northern 'Yuan Shao' territories, even though they are both under Wei control.
Anyway this is a really new strategy for me, so I decided to share it with anyone who might find it interesting.
If anyone else has developed their own unique strategy, you can put that here too.

I've just started playing this game and I've been trying to figure out something. Can you have tactics triggered while you are in your city? I'd like to use Traps, Confuse, Arrows etc on an attacker while I'm in the castle. Is that possible? Any help would be appreciated. Thanks.

Nope, you cant use any tactics from cities. Welcome to the forum btw
I'd recomend sending a unit out to fight against attackers, since you can use tactics that way