Data not saving in a newly created custom fields in a custom post.

function true_add_a_metabox() {
    add_meta_box(
        'true_metabox', 
        'Skill Level Percentage',
        'true_display_metabox',
        'skills',
        'normal',
                'high' 
    );
}
add_action( 'admin_menu', 'true_add_a_metabox' );

function true_display_metabox($post) {
    wp_nonce_field( basename( __FILE__ ), 'true_metabox_nonce' );
        $html .= '<p><label>Enter Skill % <input type="text" name="seotitle" value="' . get_post_meta($post->ID, 'true_title',true) . '" /></label></p>';

    $html .= '<p><label><input type="radio" name="noindex"';
    $html .= (get_post_meta($post->ID, 'true_noindex',true) == 'on') ? ' checked="checked"' : '';
    $html .= ' /> Expert</label></p>';
    $html .= '<p><label><input type="radio" name="noindex"';
    $html .= (get_post_meta($post->ID, 'true_noindex',true) == 'on') ? ' checked="checked"' : '';
    $html .= ' /> Proficient</label></p>';
    $html .= '<p><label><input type="radio" name="noindex"';
    $html .= (get_post_meta($post->ID, 'true_noindex',true) == 'on') ? ' checked="checked"' : '';
    $html .= ' /> Basic</label></p>';
    $html .= '<p><label><input type="radio" name="noindex"';
    $html .= (get_post_meta($post->ID, 'true_noindex',true) == 'on') ? ' checked="checked"' : '';
    $html .= ' /> Learning</label></p>';
    /*
     * print all of this
     */
    echo $html;
}