Board Thread:Question and Answer/@comment-24596086-20150324191911/@comment-25435121-20150402143556

See the Upgrade page if you haven't already. It is a great resource for finding the best way to level up your cards.

There is no drop rate chart, but the lowest rarity cards drop the most, and the higher rarity drop the least

You increase your resource limits by leveling up your storage units (like Gold Storehouse

Healing cards won't give you "free" soldiers. If your card starts the battle with 1 soldier, the healer can never increase it. If your card start with 3000/5000 soldiers, then the healer can only bring that card back up to 3000, not 5000.