I finished the game

Also from experience I found out that the population system changes a lot of your attacking philosophy. To be succesful, you want to put more emphasis on taking cities, leaving injured enemy (but not destroyed) units on the field, let enemy ships control the watera if don't need to cross, just to sabotage enemy income.
On the other side, you want to make units that are effective either cost-wise (if you have small income) or pop-wise (if you already resched the 100 pop cap and you are making like 300/turn). Fron the first category, you can find that Line Infantry and Lancers are kings. From the second, you will want to be using Grenadiers but especially Heavy Cavalry, which is exceptionally good for only 6 pop.
P. S. I can't figure out how links to some poems got between the pics. If you find them annoying, I can remove at any time, but maybe there is need for culture at any time.

I hope Crimean War will be a reason to hire Nelson. But still 1815 features no additional campaign, so technically I will be still done.