Spades are great for digging through dirt
Machetes will allow you to harvest plants efficiently
Axes are great for lopping down trees
Pickaxes help you mine ore and rock.
A big help within a game is that it'll show you when you have the most efficient tool equipped. If you tap on a cube and it gets a green outline it's ok. A red outline means the tool will be blunted much more quickly if you carry on using it.