How does Robinson Jeffers use alliteration in "To The Stone-Cutters" to draw our attention to important words and phrases?What meaning or effects...

To me, Jeffers is trying to tell us that both stone cutters and poets are trying to create things that will last forever.  He seems unsure as to whether it's worth it.  He says that everything's going to die in the end, but that poetry and stone work can last a long time even so.

I think he uses alliteration to point out the first of these -- that everything falls apart.  If you look at a couple of the places where he uses alliteration, they are in the parts where he's talking about this -- both for rock cutters (rock, records, Roman) and poets (blotted, blithe, brave, blind, blackening).  I think the alliteration draws our attention to this idea.