Send your own postcards* to the House of Representatives (US) or the Prime Minister (UK), or anyone else who you believe needs reminding of their humanity: demanding sanctions, demanding an end to weapons sales, demanding an end to the occupation and freedom for Palestine.
These are free PDF downloads, for you to print at home as many times as you wish to, adding stamps and addresses as you go. These are available in both colour and black & white versions, and a light-to-medium thickness card through a normal printer should work well in most cases.