With so many opening strategies, I thought I could share a good mid-game tactic that will work with any style you choose.
Once you've gotten the available land, bots, and have a few cities and a port or two, the game stagnates for a moment before people blindly attack each other.
In this moment, you'll likely find several players wanting to ally with you. The priority here is to focus on neighbors close to or slightly below your size. Once you have the alliance request, full-send into them, and the second they try to counter attack, immediately accept the alliance, regaining all your troops while gaining land for free. 
From here, they will have to break the alliance, becoming a traitor and getting the debuff, effectively winning you the battle. Or they can do nothing and get cucked. 
If you're able to, focus on players that are already traitors AND offer the alliance. Once again you'll full send followed with an immediate acceptance. Wait about 10 seconds then break the alliance, send another alliance request, and attack before they can accept it. If they do accept it, they have experienced the ultimate cuckoldry. 
I primarily focus on the fr*nch players, but this probably works on any player 