Possibly major spoiler ?? (Moderators please advise)

I have been watching the villagers performing their work (the farmer and researcher). If you click on a villager doing work, after a while you'll noticed a message saying "The villager improved at research". This signals when the skill level of the villager makes an increment. At this point in time, drag the villager to make him restart the routine again, because the rest of the routine does not increase "value" towards the skill.

Below, I have listed out several routines that I have observed.

Foraging -- the villager moves to a comfortable position, move his hands at the bush, bend down, straighten up again, this time with a bowl of berries in front of him (you can see the sides of the bowl peeking out, if the villager is slim), after which he will trek to the food bin. His skill level increases as he straightens up. If you want to increase his skill quickly, simply drag him to make him re-start his routine. However, if you want him to collect food, he will have to trek all the way to the food bin.

Farming -- Whether the villager is harvesting or planting crops, he will bend down 4 times, at the end of which he is either unsuccessful (shake his head), or successful (here's when his skill level increases.)

Research -- The villager will walk to a comfortable position at the table, stand to do research for a while, and then walk about again before coming to a standstill (end of research routine). Observe carefully during the period the villager is standing -- If he is unsuccessful, he will come away from the table and shake his head. Otherwise, he will bend one knee or both knees, kick his foot, depending on the villager; it is at this point that the research skill level increases, and the research points is accumulated. The rest of the routine is "useless".

Building hut -- the villager walks to a comfortable position, does some hammering and then walk off to collect a log. Upon return to the building site, he bends to put down the log before straightening up to do more hammering and ending the routine. The villager's skill level increases when he straightens up (if successful).

Using this method, I was able to quickly increase the skill level of the villagers, especially the farmer. Earlier, I discovered that if you keep the food level below 300, the villagers will stay put at their work (except for the occasional villager who will worry about food).

When I begin with the easy level, I keep one farmer, 4 researchers and one builder. I train the farmer constantly, letting him trek to the food bin occasionally to maintain food level between 270 to 310. By the time the researchers accumulate sufficient tech points for level 2 harvesting, my farmer is adept and the berry bush is going strong giving about 10 food points per trip.