Building houses is said to be good skill gain, but you can't even do that until you hit 30 [[Masonry]], and at 75 skill I personally gain no skill using my WoA/CoC [[trowel]] even after putting up 10 walls. The best way to gain skill is to simply improve [[grindstone]]s and other items that fall under the [[Stone cutting]] sub-category. Many towns don't allow [[statue]] spamming, as this contributes to lag, while [[grindstone]]s can fit in [[chest]]s and be carried easily, which is why they are preferred. The bonus to this is that you will also have higher %s on making [[stone brick]]s and [[stone slab]]s. Imping [[forge]]s and [[oven]]s is also great skill gain, but does add a large amount of clutter to an area.
Another effective way (but not as fast) is to build a guard tower. Once the guard tower is complete, you will have 30 or so masonry. Improve the tower for even more skill gain.
==Mining==