The very basic skill that a trainer needs to possess is communication. Whether it be feedback or imparting training content, all of this has to be communicated well to the trainees.
COMMUNICATION
Various styles of communication are even more beneficial as the effectiveness of the content presented can grow manifold with the level of maturity or experience the trainee batch as a whole possesses.
CREATIVITY
How well has the trainer been able to bring about enhancement and present the content in a simple yet effective and different manner every time she trains on the concerned topic.
GOOD COMPREHENSION & UNDERSTANDING
The world of training today emphasizes on the customization of content in training. Although the trainer may not know much about the industry to which the trainees belong, they should have strong probing skills to understand the work type and all the associated problems and advantages the industry is faced with. This makes it easier for content development.
PRESENTATION SKILLS
Different styles of displaying or presenting the content and its use in the trainings, to keep the interest of the trainees constantly alive and growing.
EFFECTIVENESS
That now brings us to the effectiveness of the training that the trainer needs to have a knack for and keep in mind while creating the content as well as keeping consistent checks on the same while training. Eventually, she should be able to analyze the impact of the trainees at the end of the training.
ANALYTICAL SKILLS
The trainer should be able to analyze the performance of the trainees through the simulations given to them as well as analyze one's own drawbacks, pitfalls, or strong points from the feedback received from the trainees at the end of the training session. Analyzing the need for more trainings based on the skill analysis of one's trainees and drawing up more requirements for the skill and performance enhancements of the trainees (Training Need analysis).
The very basis of the above is somewhere directly or remotely linked with creativity and strong analytical skills.
Anything over and above these will be based on the need of the organization.
Hope this answers the question, but in case of further clarification, do revert.
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Regards,
Gogo