Standard Pagination Method for WordPress - Twenty Eleven

gistfile1.phtml

The following was extracted from WordPress Twenty Eleven theme. 
If you want to integrate pagination yourself modify and used the following code snippet.

<nav id="nav-single">
        <h3 class="assistive-text"><?php _e( 'Post navigation', 'twentyeleven' ); ?></h3>
        <span class="nav-previous"><?php previous_post_link( '%link', __( '<span class="meta-nav">&larr;</span> Previous', 'twentyeleven' ) ); ?></span>
        <span class="nav-next"><?php next_post_link( '%link', __( 'Next <span class="meta-nav">&rarr;</span>', 'twentyeleven' ) ); ?></span>
</nav><!-- #nav-single -->

You can refer to Codex for changing your code further.

http://codex.wordpress.org/Function_Reference/previous_post_link