[re]define preprocess hooks for theming individual views, displays, fields, rows, etc...

template.php

// somewhere in themes/best_theme_ever/template.php

/**
 * Implements hook_preprocess_views_view
 */
function bte_preprocess_views_view(&$vars) {
  if (isset($vars['view']->name)) {
    $view_preproc_by_name = 'bte_preprocess_views_view__'.$vars['view']->name;
    //
    if (function_exists($view_preproc_by_name)) {
      $view_preproc_by_name($vars);
    }
  }
}

// somewhere else in themes/best_theme_ever/template.php

/**
 * Implements preprocess for 'news' view
 */
function bte_preprocess_view_views__news(&$vars) {
  // preprocess operations...
}

via evolvingweb.ca blog post