I would like to share some old strategy that have been shared in my groups of friends.
When attacking it is best to have atleast 2 city slot.
Why?
I noticed many players attack with just 1 city, i don't see nothing wrong with that, if it works, than by all means.
However, if you have 1 or more city slot you can capture an adjacent city, high level prefered, you can nearly double your attacking waves.
What if I have only 1 city slot?
My friend asked the same question, you can still cap the high level city if there is one avaliable, and when you have lowered the loyalty or nearly zerod him, move all troops back to the main and npc it.
A second option would be to give that newly cap city by keeping the loyalty low by using only disaster relief to increaseloyal by 5 maintaining as low loyalty, no more than 6, thus making transfering that npc city to your allies much easier. With loyalty @ 5 it gives you roughly 30 mintue to drop the loyalty to zero and thus making transfer and capturing possible within several minute apart.
This doubling wave only works if there is a high level flat to build a high level npc or a high level npc is near by.
Also an update, instant capture an npc 10 can be done with 28 waves, and can be done in 1 seconds. Thanks to DC Jerboa alot of players have contributed to perfecting this method. My friend have done an instant cap with 28 waves, while i have done a 1 second instant wave which takes more effert ofcourse it was not 28 waves, it was more like very low 30s.
Good luck and have fun.

