Though there is only one dynamic page in a blog for posts and we cannot post to more than that one page, we can create the appearance that we have posted to more than one page. We organize posts by assigning Categories to them and when we publish the software automatically displays the posts on dynamic Categories pages.

http://shade-tree-mechanic.net/tips-from-the-mechanic-himself/ is a static page that you created. http://en.support.wordpress.com/pages/ It will never update with posts because it is not a dynamic Categories page.

Delete that static page. You need to create a "Tips" Category and assign it to your posts. When you do that each time you publish a post with that Category assigned to it the post will display on the dynamic Category page.

http://en.support.wordpress.com/posts/categories/
http://en.support.wordpress.com/menus/
http://en.support.wordpress.com/menus/#adding-category-pages-to-your-menu

Here’s a link to a custom menu walkthrough > http://onecoolsitebloggingtips.com/2011/08/11/wordpress-com-custom-menu-walk-through/

There are many common errors, misunderstanding and misconceptions when creating custom menus and you can read about them here > http://wpbtips.wordpress.com/2011/12/19/custom-menus/