Improving the 'bad foot' or less preferred foot
Having a less preferred foot is completely normal, but no player should have a 'bad foot' whatever the level he/she plays at.
Sometimes the ball happens to lie perfectly in front of the less preferred foot for a clear shot. If the player has to take the time to get the ball in a good position to shoot with the preferred foot, valuable time is lost and the small window of opportunity is closed before the shot is taken. A player who instinctively takes the shot as soon as the opportunity arises irrespective before which foot the ball lies, has clearly a better chance scoring a goal or giving that perfect pass.
This way, the definition of the 'good foot' gets the correct meaning. Therefore, It shouldn't refer to the preferred foot, but to the foot best suitable to take the shot or to handle the given situation.
Still there are too many players who aren't able to do the most basic movements with their less preferred foot. Of course it is more fun for them to beat three defenders and shooting the ball in the upper corner with the preferred foot than to embarrass themselves by using their less preferred foot which they use solely as a supporting foot. "I can't so I won't". It plays in the head of many players.
Ball control drills can boost the less preferred foot to a higher level in relative short time. These drills are procedures with strict boundaries and are exactly the same for both feet.
The highest progression can be observed when a new skill is being learned, but it takes more and more effort to get to a higher level of proficiency, let alone to reach perfection.
Therefore, while a player struggles to master a new skill, more progression can be enjoyed practising this drill with the less preferred foot and by doing so making the gap between both feet smaller. Just like the preferred foot had to be trained when a player joined the game, the less preferred foot can be brought to a acceptable level in very short time as in a few months.
A player mastering the ball shows a high level of confidence which is a direct result of the first.
When a player isn't consistently able to execute a certain soccer move on training, he/she won't use the move during a game. In comparison, a player who masters it, will not hesitate to use it when the situation demands it. This player enjoys a confidence boost and grows during the game which will show during further ball handlings.
There are games where everything seems to work out well for a certain player just because he surfs on a high wave of self-confidence.
Acquiring a high level of ball mastering doesn't happen out of the blue, but only by training with the required self-discipline.