The secret of planning ahead, in short, is to divide the future into its logical compartments so that you can see it more clearly and then figure out how much you can put into each compartment. It's best to start with those who show promise, then work your way down. In picking candidates for improvement, look for those who have demonstrated interest in their work and the skills to perform well. They should, of course, already be familiar with the routine aspects of their jobs. Give them jobs with detailed instructions.
Fear of failure is often the main hurdle to be surmounted.
With enough guidance to get them through their jobs without a hitch, employees will experience the satisfaction of successful performance. In the process, they will gain confidence in their abilities. So make sure your instructions are clear, logical, and understood. It's important that they be successful on their own, so don't do their jobs for them, but advise them on details, if necessary. Give them your explicit instructions for a number of jobs, until you feel that they are ready for less guidance.