How do I output an entry author's data I have a blog. I want to output an entry author's first and last name. What is a good method to accomplish this?
For each entry, you can get the username of the author by simply using {{ entry.author }} (assuming entry is the variable containing the blog entry).

If you want to display Full name, first name and/or last name for one entry, you'd use:

{{ entry.author.fullName }}
{{ entry.author.firstName }}
{{ entry.author.lastName }}


For a list of entries and their authors, you'd use:

{% for entry in craft.entries.section('your-section').find() %}
    {{ entry.author.fullName }}
{% endfor %}