"Love is no word, but a feeling too absurd to explain." Think about something you feel strongly about. It can be a memory from your past, a very happy moment that you never expected, a moment when emotions were surging, or anything else that triggers your emotions. Your sad poetry is not only about that memory, but your feelings, as well, so try to capture them in writing.
You will need these emotions to inspire you. Taking a walk outside and surrounding yourself with nature helps you divert maximum attention to your inner self.
Laying on the grass and staring at the clouds, sitting on a swing, on a boat, or even at your desk will inspire you to let your emotions free themselves into poetic thoughts and feelings. Let the thoughts flow out of your mind, your heart, and your fingers. Whatever comes to mind — just write it, even if it's not the final draft (and, in all likelihood, it won't be). It's not necessary that you write first the beginning, and then the end. If how you want to end your poem comes to your mind, write that first, in your rough draft. And remember, it doesn't need to rhyme.
When your feelings have been released, your poem will, like magic, come to an end. Your poem should almost write itself.
Do not look at your love Poetry for a few minutes. Occupy your mind with other thoughts and tasks. Try going for a jog, washing the dishes, doodling in your journal — anything to take your mind off your poem for a bit. Doing this will ensure that you can evaluate the poem with a clear mind.