When it comes to rewards & punishment system or carrot and stick policy to motivate others, it is far more sensitive and complicated issue as supposed to what it appears to be at its face value. There are certain fundamentals that can always help the situation and objectives regarding this matter which are as follows.
Your first strategy and line of defence should be to employ some personal and social motivators, so as to help getting someone motivated in the first place and then use rewards and punishment system to do and reinforce that as well as a third line of defence or a matter of last resort, blended together with other motivators.
When it comes to employing extrinsic rewards they must be directly linked to specific vital behaviors and specific actions that you would like to be repeated and followed as well on long term basis.
When using external rewards, one shouldn’t focus on how small or big rewards are that you are considering using because when it comes to the choice of extrinsic reward, it should be genuine and heartfelt, rather than how big or small it is.
Last but not the least do your best to reward behaviors and not the outcome, as just outcomes; can be deceptive in terms of hiding inappropriate behaviors.
Now comes the hardest part called punishment or stick policy and it should be used as a matter of last resort in a very sensitive and objective way possible such as making sure to first send others a message and then employ a punishment in the most assertive way possible.