Eustace H. Miles, How to Learn Philology: a Simple and Introductory Book for Teachers and Learners (London: Swan Sonnenschein, 1899), p.254:
First get the sense, then find the flaw,
the word or words you'd fain restore :
these in a bracket now should stand
in capitals and cursive-hand.
Then try to change them for the best.
The faulty words by sense are guessed,
by metre, style of Author, next
by nearness to the given text
Show reasons for the alterations,
then add appropriate illustrations,
[N.B.] Learn all you can of MSS. :
then danger of mistakes is less.