My Wordpress directory is at www.example.com/blog
I recently changed my entire site to force HTTPS. So my .htaccess file in /blog/ looks like this:
Change the order of the rules. First redirect to https
and then let WP take over all of your requests.
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
RewriteBase /blog/
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /blog/index.php [L]