2) Google a line from the lyrics. If necessary try putting the line in quotes and adding the word "lyrics" after the closing quotes.
3) Very often the search results will return a website or two with the lyrics and the title.
4) From the title you can find details of various recordings.
5) Find the recordings on a site such as Amazon that has track preview samples. You can then check the preview to see if it's the version you downloaded.
This is always what I do (and you're right, it's time consuming). But with traditional songs you get zillions of lyric hits. Yesterday I spent several hours on one song I had stream-captured the night before: "Dogger Bank". I already have several versions of this song and, as you might imagine, there are lots and lots of lyric listings for it, each one a little different. I never did find one that matched my copy exactly. What I usually do is find a close match and edit the lyrics I put in the tag to get a perfect match to what I hear them sing.
As I indicated in my original posting, if I suspect who the artist is I always try to find a copy on Amazon or Rhapsody but neither one is very strong on traditional music - Rhapsody has 2 Dogger Banks; Amazon has one and none of them match any of mine.