There's a lot of scattered info about nginx. This is what I've deduced from reading various blogs, Debian READMEs and the nginx wiki.

For Debian I suggest installing nginx from dotdeb. They provide the latest stable versions.

For cgi install fcgiwrap

Here is a full sites-enabled/example.com configure for hosting ikiwiki on the root domain, example.com:

server {
    listen 443 default_server;
        listen [::]:443 ssl default_server;
    root /home/ikiwiki/public_html/wiki;

    index index.html;

    server_name example.com www.example.com;

    ssl_certificate /etc/nginx/ssl/example.com.pem;
    ssl_certificate_key /etc/nginx/ssl/example.com.key;

    ssl_session_timeout 5m;
    ssl_session_cache shared:SSL:50m;
    ssl_dhparam /etc/nginx/ssl/dhparam.pem;
    ssl_prefer_server_ciphers on;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2; 
    ssl_ciphers "ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:ECDHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES256-GCM-SHA384:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:DES-CBC3-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!MD5:!PSK:!RC4";
    resolver 8.8.8.8;
    ssl_stapling on;
    ssl_trusted_certificate /etc/nginx/ssl/example.com.pem;
    add_header Strict-Transport-Security "max-age=31536000; includeSubdomains;";

        client_max_body_size 10m;

        # ikiwiki site

        location / {
                try_files $uri $uri/ =404;
        }

        location ~ .cgi {
                gzip off;
                fastcgi_pass unix:/var/run/fcgiwrap.socket;
                include /etc/nginx/fastcgi_params;

        }
}


##
#Forward http to https
##

server {
        listen 80 default_server;
        listen [::]:80 default_server;
        server_name example.com www.example.com;
        return 301 https://$host$request_uri;
}

For SSL tips this gist is a good source of information. Use letsencrypt to get free certificates.