You are right about things being hard to spot.
The shadows I made intentionally hard to see, but the other guys are hard to see mainly because of the restricted colour palate. I think an outline on characters would be a good idea.
The mana should be displayed just above the end turn button, and how much the card costs is on the top left of the card. I will make this more obvious in the future though :)
Thanks for the feedback ^.^