Tips and Tricks
A popular enemy move, when they can get it on the grid, is two skulls and three swords. That makes going for hearts a little risky since you only ever get one - better to play aggressively and try to take down the enemy quickly.
Always check the shop regularly and spend gems on useful looking spells, not guff like board refreshes and similar.
Don't select a sword without at least one skull - it's a completely wasted move.
Don't be afraid to mix up your symbols.