Victoria

Her eyes
twinkle
like precious stones.

She giggles,
cooing.
Her laughter floats in the air.

Her smile,
so bright and happy,
makes my heart feel warm.

She grasps my finger,
like
she will never let go.

Oh,
my precious,
special,
baby sister.

I love her.
So much.
She is the sunshine
in my day.

I'm sure she's adorable! Thing is, the descriptions here are kind of commonplace. She's cooing, twinkling, precious. We've heard it all before when people talk about babies.
And then, the last stanza is unnecessary. If you use unique descriptions that really make this image of a baby accessible to the reader, he or she will know that the speaker cares a lot for the sister.
Also, why are the lines broken so often? It makes the poem look like string cheese.

Colleen

You really do not need all of those line breaks. There are a few spots where they seem especially arbitrary:

"She grasps my finger,
like
she will never let go."

I would really try to avoid having one word on a line by itself unless you want to place a great deal of emphasis on it. You don't need to isolate "like," as it unnecessarily breaks up your poem.

Also, don't feel as though you need to confine yourself to a form. Poetry is all about experimentation--you don't need to stick to so-many-words-per-line-per-stanza.

Anyway, cute poem overall.

The poem was good. Some of the line breaks are unnecessary and just distract the reader from the meaning of the poem. The describtion is good but could still be improved. It is a good poem and is writen with emotion which is good to see and read!

I agree with the others. I think you if use a little better
vocabulary and not so much spacing this poem would be hit.

Your baby sister sounds lovely, but I agree with Colleen, the descriptions aren't unique, they're almost cliche. Look at each description, and think about how else you can say it. For "cooing," try some onomatopoeia, think about what it sounds like when your sister..."talks," and try to incorporate that into your poem. Make some comparisons, similes and metaphors are your friends.
The line breaking was a little bit disorienting, especially since most poems that are broken up that way are sad, depressing ones. Did you feel like that was a good way to make the lines match up, with even syllables and rhythm? Rhythm is wonderful, but it's not necessary for all poems. Be a rebel! Go for freeform, sometimes that helps you let loose with more creative thoughts, since you don't have to count your syllables. Then, if you really hate freeform (I'll admit, it bothers me in my own poems, I always have to change it), go back and cut some words, add some in.
But first, go crazy. Drop the cliches, think about your precious sister in a new way.
This has the potential to be a grea tpoem, you picked a good subject. But you need to rework it. A baby is a wonderful new thing, different from anything that has ever existed or that will ever exist again. Make your poem the same way.

That was lovely - short but sweet.
I think you're right to add however many stanza's you want to a poem like that! It's already pretty short and your just emphasising your point.
There's lovely imagry in the line about her eyes - you can really picture the look on her face!