Need Help -Drupal folder/file permissions

I am having problem I think may be related to permissions/owners for Drupal folders and files.

I am finding myself constantly getting messages that permissions are wrong for Drupal functions and I am unable to edit the content of Drupal files (Templates, css files, etc.). Every time this happens I end up setting the permissions for that file or folder to 777.

I am sure it is not a good idea to set all permissions = 777 but I am not sure what the correct approach is.

One thing that I have noted is that the owner of my folders and files are not consistent. Some are 1080, some are particular users and by far most are root. I am not very familiar with Linux (of folder/file permissions) but I would imagine that Drupal itself is a user of the Linux structure and I could imagine that I am encountering situations where Drupal does not have permissions it needs.

Should I be setting the owner/group for all Drupal-related folders and files to the same user/group?

If so which user/group? Do I need to make sure user Drupal is a member of the group? Is there any documentation anywhere that describes the folder/file permission best practices for Drupal running under Unix/Linux (one that a lay person can understand)?

By the way, we have our Drupal root folder in under /opt/lampp/htdocs, do we have to do anything with the permissions on htdocs?

Thanks for any assistance.