Simply paste the following snippet of code into your theme's functions.php file and adjust the CSS on line 4 as needed.

/** ******** ******** ******** ******** ******** ******** ******** ******** 
* TITLE: Beautify the Log-in Page
* DESCRIPTION: Make the Log-in Page PRetty
* 1: Change out Logo
* 2: Change out URL
* 3: Change out Title
* 
* http://codex.wordpress.org/Customizing_the_Login_Form
*/
function my_login_logo() { ?>
    <style type="text/css">
        body.login div#login h1 a {
            background-image: url(/wp-content/uploads/2014/07/logo-80x80.png);
            background-size: 80x 80px;
        }
    </style>
<?php }
add_action( 'login_enqueue_scripts', 'my_login_logo' );

function my_login_logo_url() {
    return home_url();
}
add_filter( 'login_headerurl', 'my_login_logo_url' );

function my_login_logo_url_title() {
    return 'GuitarPick';
}
add_filter( 'login_headertitle', 'my_login_logo_url_title' );

function no_errors_please(){
  return 'Please Try Again';
}
add_filter( 'login_errors', 'no_errors_please' );