The overtraining tip for Clash of Clans is quiet common and pretty simple. But ’cause of its usefulness, and I think that there are still many guys haven’t heard about it yet, I’ve just decided to show you about it in this post.
As known, Barracks and Dark Barracks allow you to queue troops for training. The maximum number of troops depends on the Barracks’ level. You can use this advantage for two purposes: Hiding your resource and saving time while you’re doing an attack.
The battle can take up to 3 minutes every time you attack. It’s mean you can have over 30 troops after a raid, and even more if you use Dark Barracks. When you’re out, just train the most expensive troop as much as you can. The barracks will take off your elixirs. And when you’re back, just cancel all the queued troops in the barracks and take your elixirs back.
Hope this small CoC tip will be useful with you! Source