When you do a thorough job of using appeals to reason
in your argument, showing that you've carefully considered
the issues, and done the necessary work to formulate a well-supported
argument, you have shown the reader that you are trustworthy.
Readers are more apt to consider your position if they believe
you have sufficient knowledge of the subject, and if you show
them that you care about their needs. This is one way of appealing
to an audience through character.
You can also engage readers with more direct character appeals. For
example, if you are a parent, you may be able to appeal to readers
who are parents more directly by making a connection between yourself
and these readers. When a reader identifies with a writer, the reader
is more likely to agree with and be persuaded by the writer.