This poem has a lovely mood of summer mornings and the joy and hope that they bring. I can see a couple of places where similes may fit nicely without spoiling the natural rhythm and original metre too much. For example, how about closing your eyes and imagining humming bird wings? What are they like to you? To some people they might be pretty and delicate (like the wind ruffling through a flower's petals) - to other people they might be more strong and powerful (like an aeroplane propeller.) Think about which image fits the mood of your romantically set poem, and then shorten the simile you picked so it flows nicely and smoothly with the rest of the text. Move down the poem looking for other mentioned objects and do the same.