Those themes are worth writing about - as long as the writing is fresh and convincing. Instead, use concrete images and details to pull the reader into your poems. Often, the mood and tone we set in our poems is not set by the feeling surrounding it, but rather the objects and setting we choose to include, and how we choose to describe them. For instance, a beach may be considered a romantic setting, but in Eliot's poem, it is used to convey the despondency of an aging man walking alone on a beach, hearing mermaids singing their songs of seduction, but not for him. The careful and deliberate placement of these details is what makes the poem, and lets the reader in to the subject's loneliness.
Poetry is a unique medium.
It offers a chance to say great things with few words. Don't spend them all in one place. Look at one poem you've written in the past and find at least one weak phrase. Experiment with as many alternatives as you can come up with, based on the idea that details, imagery and precise word choices will create a stronger piece. Focus on sense imagery to create mood.