Begin with a list of people who are distant or hard to reach (for whatever reason). Lighthouse attendants, prisoners, sherpas, polar explorers. Distance is key.
Next, make a list of forms of communication. Telephone, text, Twitter, letters, telegraphs, etc.
Match up a pair from the two lists that have some friction. Don't worry about how likely or unlikely they might be together. Write a poem to this other person. Relate to whatever it is that put them in that distant place, whether it's chance, circumstance, choice or poor decisions. Reach out to them as if they need to hear from you (even if they don't realize how much they need it, or who you are).
Take a look at Keetje Kuipers Letter to an Inmate in Solitary Confinement over at Poetry Daily, then get to work