When you hear poetry, you can often hear a nice rhythmical sound. It is a little bit like the beat you hear in music.
Listen to this sound: i AM bic Iambic feet go: i AM i AM i AM i AM
Clap your hand to this sound, clapping on the heavy beat. This is called metre in poetry.
Clap your hand to the heavy beats in this line of poetry:
I SEE two SQUIRrels IN a TREE (There are four beats, or feet as we say in poetical language).
Try another line:
I THINK they're LOOKing DOWN at ME
There are four feet (beats) in each each line, and the first line rhymes with the second line.
Let's try another two lines:
I've SEEN a VERy LIVEly FROG,
A CHILD on SWING; aNOTHer DOG
So we actually have the first verse of a poem, and we say that the rhyming is aabb (that is, the first two lines rhyme and the second two rhyme). With four beats per line and with this rhyming scheme, it is called TETRAMETER.
Try writing some iambic lines with four beats per line yourself. I'll start you off:
My MOTHer's COMing TO our SCHOOL
Next TUESday I won't GO to WORK
The BUS came ROARing DOWN the ROAD
Two RABbits RAN aCROSS a FIELD
Notice that iambic meter has one light beat followed by a heavy one and the stresses on the words must be where they naturally occur in your speech. You mustn't change that. HOWEVER, I must emphasize that it is quite normal to start the poem on a heavy beat and also some verses, and for the last line to have a double short beat. This is for emphasis.
Now, in case you want some more help, please go here:
See these poems
(and many more):