> A training program that acclimates new members to the system. If terms are say, six years long, then the first year can be entirely devoted to training.
A more organic version of this would be to select at random from people who already served at a lower level. Pick random citizens for city council, then for state you pick from the pool of people who have been city councillors in the past, then for country you pick from people who have already served at the state level. You could, in addition, add past picks to a "veteran pool" to ensure a small percentage of the legislature has been there before and can suffuse their experience.
A more organic version of this would be to select at random from people who already served at a lower level. Pick random citizens for city council, then for state you pick from the pool of people who have been city councillors in the past, then for country you pick from people who have already served at the state level. You could, in addition, add past picks to a "veteran pool" to ensure a small percentage of the legislature has been there before and can suffuse their experience.