Three very important and useful tools that any writer should have in his "toolbox" are:

Alliteration (uh-li-ter-ai-shun)

Assonance (a-soh-nunce) (soft "a" like in an)

and

Onomatopoeia. (ah-no-mah-toe-pee-uh)

The one most probably recognized is alliteration. Very simply, alliteration is the use of words with repetitious vowels or consonants, generally closely spaced, if not one right after the other.

Repetitious consonants are called, consonantal.
Repetitious vowels are called, vocalic.

Some examples of alliteration are:

from stem to stern (consonantal)

apt alliteration's artful aid (vocalic)

on scrolls of silver snowy sentences (consonantal)

The rhythm established by alliteration, as in the examples, is very appealing, has a tendency to move the reader smoothly through your lines, and is helpful in creating images and visions for both--the reader and the writer.

Assonance is closely related to alliteration. Assonance, however, is characterized by the repetition of vowel sounds. This would include vowel rhymes with the same sounds, but with different consonants.

Examples of assonance are:

penitent

reticence

Assonance is useful when the writer wants to create a melodic effect, but wants to use consonants to establish dramatic impact.

Onomatopoeia is probably the most fun of these three tools.

It's nothing more than using a word that has the same sound or action that the referent object would make or take. It's more recognized for the sound qualities, however.

Examples of onomatopoeia are:

a hooting owl

a clicking crab

a buzzing bee

An interesting line to study is:

The clicking crab clawed clumsily while buzzing bee buzzed angrily.

That line has elements of all three--alliteration, assonance, and ono...what!?

Some writers have been gracious enough to mention that my works have a certain "quality" about them, and one which they would like to emulate. I use a lot of the tools above. They're helpful to me to establish rhythm, or rhyme, or meter, or just interest to beguile the reader.

I hope they will be helpful to you, also. ^_^