What is the required format for importing posts into WordPress?

I have several posts in an Microsoft Excel file (.csv/.xls). I want to know the appropriate format of the file to import into WordPress.com.

Note: I do not need help to convert the csv format into xml. I just need to know the required format for feeding into WordPress. Same approach should work for .org hosted blogs.

Currently I have extracted a WordPress XML file from WordPress with the necessary headers. I believe all I need to do is populate the below XML code for each new post.

What fields can be excluded? What fields can be left blank? An example of successfully imported file and code would be appreciated.

I have tried two imports into WordPress that have been confirmed as successful however I cannot see either post? So I suspect something is wrong with my file.

 <Item>     
      <title>   My Post Title   </title>
      <link>    My Post URL </link>
      <pubDate> Sun, 01 Jan 2012 00:00:00 +0000 </pubDate>
      <dc:creator>  Author  </dc:creator>
      <guid isPermaLink="false">    My Post WP URL  </guid isPermaLink="false">
      <description> My Post Description </description>
      <content:encoded> My Post Content </content:encoded>
      <excerpt:encoded> My Post Excerpt </excerpt:encoded>
      <wp:post_id>  My Post ID  </wp:post_id>
      <wp:post_date>    2012-01-01 00:00:00 </wp:post_date>
      <wp:post_date_gmt>    2012-01-01 00:00:00 </wp:post_date_gmt>
      <wp:comment_status>   Open    </wp:comment_status>
      <wp:ping_status>  Open    </wp:ping_status>
      <wp:post_name>    My Post Title   </wp:post_name>
      <wp:status>   inherit </wp:status>
      <wp:post_parent>  My Post Parent ID   </wp:post_parent>
      <wp:menu_order>   0   </wp:menu_order>
      <wp:post_type>    attachment  </wp:post_type>
      <wp:post_password>        </wp:post_password>
      <wp:is_sticky>    0   </wp:is_sticky>
      <wp:attachment_url>       </wp:attachment_url>
 </Item>        

Here is an import file where only a few settings are used (although you may be able to exclude even more), which successfully imports three posts (tested on WP 4.2.2):

<?xml version="1.0" encoding="UTF-8" ?>
<rss version="2.0"
    xmlns:excerpt="http://wordpress.org/export/1.2/excerpt/"
    xmlns:content="http://purl.org/rss/1.0/modules/content/"
    xmlns:wfw="http://wellformedweb.org/CommentAPI/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:wp="http://wordpress.org/export/1.2/" >

    <channel>
        <wp:wxr_version>1.2</wp:wxr_version>

        <item>
            <title>My first post</title>
            <dc:creator><![CDATA[admin]]></dc:creator>
            <description></description>
            <content:encoded><![CDATA[
<p>Welcome to my first post!</p>
]]></content:encoded>
            <excerpt:encoded><![CDATA[]]></excerpt:encoded>
            <wp:post_date>2015-03-01 16:20:00</wp:post_date>
            <wp:status>publish</wp:status>
            <wp:post_type>post</wp:post_type>
        </item>

        <item>
            <title>My second post</title>
            <dc:creator><![CDATA[admin]]></dc:creator>
            <description></description>
            <content:encoded><![CDATA[
<p>Welcome to my second post!</p>
]]></content:encoded>
            <excerpt:encoded><![CDATA[]]></excerpt:encoded>
            <wp:post_date>2015-03-02 16:20:00</wp:post_date>
            <wp:status>publish</wp:status>
            <wp:post_type>post</wp:post_type>
        </item>

        <item>
            <title>My third post</title>
            <dc:creator><![CDATA[admin]]></dc:creator>
            <description></description>
            <content:encoded><![CDATA[
<p>Welcome to my third post!</p>
]]></content:encoded>
            <excerpt:encoded><![CDATA[]]></excerpt:encoded>
            <wp:post_date>2015-03-03 16:20:00</wp:post_date>
            <wp:status>publish</wp:status>
            <wp:post_type>post</wp:post_type>
        </item>

    </channel>
</rss>