Here is a link of commonly used template tags and their purpose.
- the_permalink() - Displays the URL of your post
- the_title() - Displays the title of the post
- the_ID() - Displays the unique ID of your post
- the_content() - Displays the full content of your post
- the_excerpt() - Displays the excerpt of your post. If the Excerpt field is filled out of the Post edit screen, that will be used. If not, WordPress will auto-generate a short excerpt from your post content.
- the_time() - Displays the date/time your post was published
- the_author() - Displays the author of the post
- the_tags() - Displays the tags attached to the post
- the_category() - Displays the categories assigned to the post
- edit_post_link() - Displays an edit link that is shown only if you are logged in and allowed to edit the post
- comments_popup_link() - Displays a link to the comments form of your post
And for completion..