[rramadass]

The number one advice i can give you is;

1) Do NOT kill their Motivation, Enthusiasm, Energy by too much criticism in the beginning.

Once you have given them a problem, only monitor and provide hints as needed to help them solve the problem themselves i.e. you are only an animated "Rubber Duck". Let them get to some solution, its quality does not matter initially. Learning is a process of trial-and-error and adding of one knowledge chunk at a time to a mental model which you are building up during the process itself. Once they have a solution ready, congratulate them on their success which boosts their confidence.

Now comes the hard-part i.e. a postmortem of everything they have done where you point out mistakes (eg. edge cases which they have failed to consider, code design standards and correctness, proper documentation etc.) and show them how it is done professionally in the workplace. This will bring home the difference between "Hobby/School" vs "Industry" solutions. They then can rework their solution with these code characteristics in mind to come up with a "industrial strength solution".