Prevent access to your .htaccess file

<Files .htaccess>
order allow,deny
deny from all
</Files>

# Rename the file
AccessFileName thehtfile.ess

Prevent URL attacks

# Enable rewrites
RewriteEngine On

# Block <script> tags from executing in the URL
RewriteCond %{QUERY_STRING} (<|%3C).*script.*(>|%3E) [NC,OR]

# Block scripts from setting a PHP Globals variable
RewriteCond %{QUERY_STRING} GLOBALS(=|[|\%[0-9A-Z]{0,2}) [OR]

# Block scripts from using base64_encode
RewriteCond %{QUERY_STRING} base64_encode.*(.*) [OR]

# Block scripts from using the a_REQUEST variable
RewriteCond %{QUERY_STRING} _REQUEST(=|[|\%[0-9A-Z]{0,2})

Disable use of scripts on your directories..

AddHandler cgi-script .php .pl .py .jsp .asp .htm .shtml .sh .cgi
Options -ExecCGI

Enabled directory index means that if someone access to any folder which don't contains index.php , index.html, index.htm or any other default file defined in DirectoryIndex in apache configuration then all files in that folder will be listed in browser if you try to visit that page.

Often directory index is enabled by default on your apache server, in these cases good security practice is to disable directory index with following line:

Options -Indexes