Here are a few links from a website that has commentaries and sometimes essays on poems (see the links on the left of the their website)
"How Shall I Love Thee" by Elizabeth Barrett Browning
"Do Not Go Gentle Into That Good Night" by Dylan Thomas
"God's Grandeur" by Gerald Manley Hopkins
"The Love Song Of J. Alfred Prufrock" by T.S. Eliot
Starting to read poetry: form and langage
Lyric Poetry: poetry's many forms
These web pages and others that you may find at Suite101 will help you annotate your AS anthologies. Other exam boards seem well catered for as well.