If I want to add a new source i have to
copy address -> open selfoss -> goto Sources -> add new -> select rss-handler -> paste the link -> type in title or go back and copy again -> fill in tags -> save

Would be nice to point new feeds to something like http://your.selfoss.com/?addFeed=%s which would fill in Name and Url of %s into the AddSource Page.

Many Browser/Addons show an customizable Add Feed-icon in the titlebar and simply send the feed-url to an api which would reduce the above to
click rss symbol -> (click abo) -> fill in tags -> save

Possible enhancements/problems:

• autodetect source (like twitter or tumblr), otherwise default to rss-feed
• on the fly mode: add NEW label and save without further interaction for rss handler without redirect.