Theory:

The pattern of rhymes at the ending of each line in a poem is called a rhyme scheme. Letters (A,B,C...) are usually used to express which lines rhyme. Verses that are designated with the same letter are said to rhyme with each other. It is also known as an arrangement of rhymes in a stanza or a poem.
Example:
1. For easier understanding of the concept, let us take a famous nursery rhyme, written by Jane Taylor as an example.
 
Twinkle twinkle little star,
How I wonder what you are.
Up above the world so high
Like a diamond in the sky.
We see that the first two lines rhyme with each other (star-are); the second two lines rhyme with each other (high-sky). Let us name each line as \(A\), \(B\) depending on the words that rhyme with each other.
 
Twinkle twinkle little star,
A
How I wonder what you are. A
Up above the world so high,B
Like a diamond in the sky. B
It can thus be seen that this poem follows \(AABB\) pattern.

Rhyme scheme of the poem "Lessons in Life" - written by Daniel Ho / Bridgette Bryant, is as follows:

Having a friend is like planting a flower
A
Show love and kindness it one day will bloom
B
Let’s be aware as we walk on this planet
C
Even the tiniest creature needs room.
B
 
 
Lessons in life aren’t always so simple
D
Nothing you’re given will ever come free
E
Even the smallest of gifts deserves “thank you”
F
I respect you and you respect me
E
I think of you and you think of me.
E
 
 
Remember everyone here is important
G
When you’re forgotten it makes you feel sad
H
Know that you matter and you make a difference
I
Let no one shame you or make you feel bad.
H
 
  
Lessons in life aren’t always so simple
D
Nothing you’re given will ever come free
E
Even the smallest of gifts deserves “thank you”
F
I respect you and you respect me
E
I think of you and you think of me.
E
 
Important!
The overall rhyme scheme of the poem is \(ABCB\ DEFEE\ GHIH\ DEFEE\).