Jot down a list of the things you find especially enjoyable about math. Any features that it has, any qualities of problem solving, anything that makes you giddy, you should write down.
Remember what your terms mean in plain English. Write down ideas for word play based on this and start toying around with line ideas.
Select an ode form. From Pindaric to Horatian, to a more customized structure, meter and rhyme scheme helps you determine how to proceed.
Determine your opening line. It should be a good one that draws in the reader and gives them a taste of how you feel. It doesn't have to have much explanation.
Write the body. This is the most challenging step. Stick to your form and know that if you don't already have a rhyming dictionary, you can find a rhyming dictionary at Rhyme Zone.
Sum up with a line that tells the beauty of your mathematical expression. Don't go off on a tangent or recurse the language. Your vector should be true to your end point.