The heroic couplet consists of two rhymed lines of iambic pentameter that is a rhetorical unit; that is, it expresses a whole thought. Shakespeare's sonnets end with heroic couplets. Here is some Shakespeare:
End of Sonnet XIV
Or else of thee this I prognosticate:
Thy end is truth's and beauty's doom and date.
End of Sonnet XVIII
So long as men can breathe, or eyes can see,
So long lives this, and this gives life to thee.
End of Sonnet LXXXVIII
Such is my love, to thee I so belong,
That for thy right myself will bear all wrong.
Here are two entire poems by Robert Frost, each of which is one heroic couplet:
From Iron
Nature within her inmost self divides
To trouble men with having to take sides.
[Fogive, O Lord..]
Forgive, O Lord, my little jokes on Thee
And I'll forgive Thy great big one on me.
William Butler Yeats: The Statues, (1939) This couplet ends the poem:
Climb to our proper dark, that we may trace
The lineaments of a plummet-measured face.
Also be Yeats: Vacillation (1933) ending verse three:
No man has ever lived that had enough
Of children's gratitude or woman's love.
Rhyme is not as common an element in serious poetry as it was in the past; if you enjoy writing poetry, read some good current poets and see if you can write rhythmically and expressively without falling into the trap of mangling lines to force a rhyme.
Emdrgreg