Raspberry and Cream

Ooo! It has a lot of potential.

First of all, I think this can have linebreaks where you put the commas. So it would look like this:

Raspberry and Cream

Marcia’s by the lake again,
Sipping raspberry and cream.
Though I doubt the fairy will join her,
or so it’s going to seem

Marcia’s by the lake again,
eating raspberry and cream.
How I know the birds will watch and flock down with glee
Though Marcia is greedy and will shoo the birds away.

Marcia’s by the lake again,
smelling raspberry and cream
I hate to see her lose her time,
waiting for the tide to leave.

Marcia’s by the lake again,
waiting for the fairy to arrive.
I know they will show,
and perform before her by the shore.

How do I know they will come?
Because sticky fingers are no more.

This has a very singsong pattern to this, heightened by the repetition of the first two lines (but with variations, fortunately for us!)

You mention, straightaway, that Marcia (nice name choice, by the way) is enjoying herself, waiting for the fairies to arrive. But, instead of saying that she's waiting for the fairies, you tell us that you doubt the fairies will come. So! I think ordering is a good thing in this case. First, the reader has to know that she is waiting for fairies. Second, the reader has to know that you are doubtful whether the fairies will join her. Next, we see she's still waiting. Finally, the narrator of the poem recognizes that the fairies will come.

These lines are a bit unruly:

How I know the birds will watch and flock down with glee
Though Marcia is greedy and will shoo the birds away.

I think they look too big. Try cutting down words to make it look a little smaller. Remember, writing poetry isn't just about what sounds good. It also has to be appealing to the eyes.

Oh, and I realize I said fairies instead of " the fairy." I think you should make it plural. It makes for a better image.

But otherwise, nice poem!