how do the sounds of the words and the poet’s use of devices, such as alliteration, contribute to the meaning and the mood of the poem

Question

http://mrbraiman.home.att.net/lit.htm

This site will give you a list of literary devices... and the usages.

Think of this for instance. "mighty like a rose" That is a simile... The poet is comparing is love to a rose which is probably the ultimate symbol for a beautiful woman. He doesn't have to say anything else...he has used the epitome of beauty.
Irony is very often used for humor...When the unexpected happens more often or not the result is humor.
" The ant has made himself illustrious
Through constant industry industrious.
So what?
Would you be calm and placid
If you were full of formic acid?"
Pure irony. Ogden Nash is the master of poetic irony.

http://www.poetsgraves.co.uk/glossary_of_poetic_terms.htm
"Alliteration The effect created when words with the same initial letter (usually consonants) are used in close proximity e.g. Ariel's Songs from The Tempest 'Full fathom five thy father lies'. The repeated 'f' sound is alliterative. Alliteration is sometimes referred to as head rhyme. Other examples of alliteration include: 'Only the stuttering rifles' rapid rattle' from Anthem for Doomed Youth by Wilfred Owen and the amazing five consecutive 'ds' in The Windhover by Hopkins - 'king-dom of daylight's dauphin, dapple-dawn-drawn Falcon'."

I hope this has given you some good ideas.