I just discovered this, never knew you could do it. Might be old news to some of you, but it's really handy.

When you are sending out lots of identical attacks to diffrent cities (usually farming) you dont have to keep typing the troop numbers in.

Send your first attack, then when you get the "March Successful" dialog, click [ok] then click [favorites] then click [x] to exit.

Then select your next target and attack. The troop numbers will still be there and all you will have to do is add a hero and march.

Hope this helps, Happy Hunting