Include (or allow enabling) an RSS feed for each individual tag, in addition to the full feed. This allows readers to subscribe to a certain subset of posts, should they not be interested in everything you write.
Per tag feeds would be really useful - for some, me included, this would be a nicer alternative to multiple blogs.
This is now available by using the ?q=tagname
parameter on the RSS feed. Eg: http://herman.lh.co/feed/?q=writing
will be a writing
tagged RSS feed