Got myself puzzled for a bit while slicing a WordPress theme this weekend on how to get a permalink to a certain page in WordPress template, given that you know what’s page title. Use this:
<?php echo get_permalink(get_page_by_title("Page title here")->ID); ?>
So now in your template you can use like this:
<a href="<?php echo get_permalink(get_page_by_title("About")->ID); ?>">About</a>