I don't think there's really any secret, except to start the villagers with the right aptitudes at the right time in the game. Farming, Building, and Research are probably the three easiest to master, but building may become difficult at various times in the game, depending on what's available to work on.

Parents are easier to develop after they get older (they are free to make love without the risk of pregnancy).

Other than that, I don't know what else to suggest. Every villager has different aptitudes to different tasks, so some will be easier to make elders than others.