Scansion
When it comes to scansion, the best way to learn is by trying it out yourself. Of courses, the only way to know if you are improving and getting better is by having a reference to work from. For Better for Verse is an interactive tool created by the University of Virginia that will help you develop your skills from a beginner level to a proficient level.
As you can see on the examples on the left, in this site you will be able to try your hand at scansion and the software will tell you when you have gotten your scansion right, or wrong. You can even find some poems by Hopkins, in the Special Challenge category, of course.