I have been toying with some features and how to implement them. So far, I have come up with the following:
Many resources occur naturally and must be captured in order to produce anything from them. Examples include timber, mineral ores, etc. Based on this, I have been working on a more or less intuitive approach to harvesting.
Mining- Characters may "prospect" an area to determine it's mining potential. After that, they may "prospect oretype". More difficult ores require greater skill to discover and may not be available in all terrain. A successful prospector will reveal a vein of ore that may be prospected for information on how much it may produce, it's mineral type, etc. Miners can then "mine" the vein to obtain raw ores, crystals, etc. Veins do have a limited amount they can produce before being exhausted.
Lumber- Characters may attempt to harvest trees in wooded areas. The woodcutter simply "fell"s a tree in the desired area. The character will then attempt to identify a suitable lumber tree and cut raw wood. Sites can be stripped of usable lumber by over harvesting, but trees will grow back
Farming- Characters may "plant" seeds. Over time, they will grow and may be "harvest"ed. Some plants must be further processed by milling, grinding, etc. Many plants grow wild, and may be a good source of seeds. Seeds may also be planted in certain containers if soil is added. Careful care ensures that these seeds are more likely to survive and may then be transplanted to the ground where they can absorb natural nutrients (but are also more vulnerable to inclement weather).
Liquids- Water is perhaps the most common occurring liquid. Characters can fill suitable containers from water sources. Care must be taken to inspect water sources, however, to make sure they are not stagnant and contaminated. Other liquids that may be useful include honey, blood, etc.
Animal Parts- Animals may produce items such as meat and fur that are very useful. In order to obtain them, the character must first slay the animal, then use a bladed instrument to "butcher" the carcass. Generally, this will result in meat, hide, bones, and blood. Some creatures may have more exotic parts such as horns, wings, fangs, etc. Butchering human remains is generally quite frowned upon, but some barbaric types are known to obtain grisly trophies this way.