Now, how to make skills effects (like brickmaker level 3)? The skill can not affect quality (bricks are always the some quality), can't affect resources spend (not very realistic, plus the numbers are low) and letting the player do it "faster/easier" is not good because stamina cost is low too (stamina cost is like 3).
In short the basic formula is like that: 1 clay + 3 stamina = 1 brick. Not much to work with...
The only solution I see right now is to add a chance to "refund" a bit of stamina. Like each level of brickmaker skill gives you a 5% chance to -1 stamina cost when making a brick (so level 3 means 15% chance for 2 stamina cost and 85% for 3 stamina cost). Any other solution?