Thank you all for your answers,
so basically if you don't want to fight a war just yet, the best answer is probably to expand more and spam improvements everywhere (and pay for them). However, money is never the problem for me in Ea, don't know if that's the same for you guys, and I almost never play as a merchant nation and very rarely open a trade route with foreigners.
If the druid casts Ea blessing, it can easily turn the LT strength up to 30 or so... this basically means 30 choppings, which a) is quite tedious and b) gets you a crazy lot of timber. In my not-so-recent game (I believe it was Ea 7f) I got something like 60-70 timber. And with timber you can make lots of money; interestingly, you only can sell 5 copies of copper (ok, maybe 9 if you're smart and trade 4 copies for 6 gpt first, and then 5 more for 7 more gpt, sometimes it works this way). However, I managed to sell smth like 20 timber to one AI, each time full price and we weren't friendly or something.
This, in principle, can be seen as a exploit; say, the LT strength is about 30, which means every three turns it gets back. It takes three turns to chop a forest; so every 5-6 turns you get 2 timber per worker (and per tile), and a worker costs how much? 2 gpt? Now, two timber you can sell for 3 gpt, the trade lasts 30 turns, right? In 30 turns you get 2*(5 or 6)=10-12 timber which can be sold for, say, 14-18 gpt (4 timber per 6 gpt or 5 timber for 7 gpt). But anyway, everyone has soo much money in Ea that these numbers hardly matter.
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While typing this little commercial overview, another thing came to my mind I wanted to share with you some time ago. When the AI has the last copy of a regular luxury resource (wool, gems etc, anything they get from tiles and improvements), in Ea (as well as in the base Civ) they sell it for 3 luxuries, as usual. However, luxury resources they get from buildings (ale, spirit, porcelain etc) can be traded 1:1 even if that's their last copy.