The worst thing you can do when developing your staff/team members is to set them up for major failure (the second worst is not bothering to develop them at all).

For instance, you hire a recent business graduate with lots of potential and then put them in a position far beyond their experience level. The person then messes up really bad, maybe loses a key account or mismanages the team such that productivity drops or key employees quit. You will have to "fire" them from their position. This can devastate the individual and quite literally ruin their level of respect in the company. This can set them back years.

Or say you just hired an intermediate programmer. Good solid development skills but no knowledge of your business domain or enterprise level issues. You give them a very important and complex project because you are short on staff and they are smart. The person gets into the project, realizes they are in way over their head, starts to fail and takes a job at another company get away from the failing project.

In both these cases, you have either failed to develop, set back or lost very good talent.

Now suppose you took that up and coming developer or business manager and coached them properly.

You give them progressively more challenging assignments, always being sure that the individual has a good chance of succeeding at the current level. Some failures are ok but they should not be devastating, but rather learning experiences in and of themselves.

Lots of coaching along the way and the person builds skills and confidence as they go. The challenges eventually can get bigger and the person can be pushed further out of their comfort zones as their skills improve… including the ability to deal with failure.

I ran into an expression early in my career, "People are promoted to their highest level of incompetence".

What this means is that they are often promoted based on their performance in their last job and since they are up and coming… too fast and too far. They failed to develop the skills to succeed at that level (they were never really being coached). What happens is the person cannot be demoted to learn the requisite skills to be competent at that level so they languish in incompetence; unable to be promoted and resented by their subordinates.

As a leader/manager you want to promote people to their highest level of competence. When they are better able to stretch, you can make the increments bigger. But remember to keep coaching, it is still in your best interest for your team to succeed. Know their limits and customize the path for each person worth developing.

The same basics apply to your own personal self-development. Keep progressing incrementally so you are growing through success. Success builds momentum.