Customize the submitted by block by adding this code to the template.php. Remember to change the bolded theme_name_preprocess_node with the name of the theme.

When optimizing css and javascript it can be done with a few clicks. The best way to optimize it, is by compressing and caching both.

Locate them at admin > configuration > development > performance. There you'll see two options:

1. Aggregate and compress css files.
2. Aggregate Javascript files

Check both items and viola, your site is optimized. Keep in mind that these settings should be on for the live site.

Fixing the errors are difficult. Especially, when the error report has been set none and you've end up with a blank white page (known as white sceen of death). Here's a list of things to try:

Working with drupal, you'll run into many errors. For the live environment, hiding the errors and surpressing them will close the floor gates of reported errors. For dev environment, showing all errors is very beneifical to developers and finding what module is the problem child.

Find the settings by going into the admin, Configuration > Development > Logging and errors. The options are self explaintory.

Sometimes you need to control the number of post on the front page. You can find it going Configuration > System > Site information.

The rest of it is self explainatory.