This couple of simple URL rewriting rules will help you avoid some mistakes that are syntaxically legal and therefore might be referenced upon a bad backlink to your website or something.

# Multiple slashes
RewriteCond %{THE_REQUEST} \ (.*)//+(.*)\  [NC]
RewriteRule ^(.*)$ %1/%2 [L,R=301]
# Trailing dot on domain
RewriteCond %{HTTP_HOST} (.*)\.$
RewriteRule ^(.*)$ http://%1/$1 [L,R=301]
# Trailing question mark
RewriteCond %{THE_REQUEST} ^[A-Z]+\ /[^\ \?]*\?($|\ )
RewriteRule ^(.*)$ /$1? [L,R=301]
# Trailing slash(es)
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/$ http://%{HTTP_HOST}/$1 [L,R=301]