As a teacher of Blake at A-level I cannot recommend this study guide highly enough. But listen, this is in no way a substitute for reading the poems over and over and if you want a lazy way to improve your grades then don't bother. It's a sad fact that studying a text or texts for examination these days tends to squeeze the fun out of them; Blake's poetry is ripe for analysis but is never going to leap off the page at you unfortunately.
With sections on language, style, motifs, context, and structure, this is a vital tool for students. I strongly urge you to buy a copy from Amazon as you get the best price here, and buy it BEFORE you start to study the poems.