Removing duplicate UTF-8 meta tag information of a Drupal generated page
You may see twice the meta tag http-equiv="Content-Type"
Which is not very elegant, so one of the simplest solutions is to locate in your template pages the file: page.tpl.php and erase the line:
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
Running cron
Maybe in your hosting options you have no access to cronjobs, the planified jobs that can be executed every day automatically. The cron job can do things for you like emptying cache and deleting unused records from your database.
You can launch cron manually go to your browser and type: http://mysite.com/cron.php
Well, replace mysite by your own site name.
That's it!
Installation errors
If you are getting installation errors like:
install error Call to undefined function _drupal_maintenance_theme()
Check on your uploaded files, some host may have ftp quotas, so you will upload empty or incomplete files, reload everything and go!
Clear cache
Go to: admin/settings/performance#edit-clear
Drupal is asking to reinstall!
Recently I've made the mistake of trying to change the files directory permissions with the FTP client, this created a permission conflict and the site didn't work! Is was asking for a new instalation!
So, this is how I've solved it: I've changed the whole /sites/default permissions to 777 (there is nothing wrong as later Drupal will change permission to the correspondigns 644).
The problem was that Drupal didn't have access to the settings.php files.