A skillset is something that someone can be considered proficient in (aka "good at"). Playing guitar is a skillset. The same is Cold calling a prospective client.
In order to identify if something is a skillset, try asking the following questions:
If the answer to at least one of the above questions is "yes", then you are probably dealing with a skillset.
Skillsets are broken down into the particular skills on is expected to be able to perform/know in order to be considered proficient in the skill. Skills can be broken down into subskills where neccessary.
In the context of the Playing guitar skillset, skill examples might include
Skillsets are sometimes confused with the closely resembling information types skills and policies.
Here's how to think about these three information types in order to better distinguish between them.
Describes expected proficiency/level of mastery. Collection of singular skills.
Describes a singular ability one is expected to be familiar with in order to be considered proficient in the parent skillset.
Describes expected behaviour.