To force your next turn in the game, you must first remove a queued unit from the production tab and then click the Next Turn button. This will save the production turn for the city that has the queued unit. If you don’t remove a unit, you can prolong the turn indefinitely by queueing the unit indefinitely. Alternatively, you can also force the next turn of production by attacking the city.
Trick for attacking the city
The AI is prone to losing its attack on a bait unit. This can be avoided by placing a melee unit on a mountain or plains. If you place the unit behind a unit with ranged attack, you can still use the city to ward off incoming attacks. Additionally, if the unit is cured by the medic unit, you can swap it with it. This trick works for both melee and ranged units.
You can also place a siege zone around a city to restrict enemy movement. This will allow you to attack a city with less units. If you place three units around a city, it will be under siege. If your enemy army attempts to enter your city, it will be prevented by a heart icon displayed in the city’s name box. However, this zone cannot extend over rivers. This trick will immediately ruin your relations with the enemy nation.
Using Mobile Units is another trick for attacking a city. Mobile Units start off as Horsemen, but eventually they will upgrade to Cavalry, Tanks, and Warships. This trick is great for pillaging tiles, but it can also lead to Civ Unhappiness if you attack the City with ranged units. Make sure to protect your traders, or else you’ll end up with a barbarian-occupied city.