I’m not an ex-pat (yet lol), but writing letters and sending postcards is helpful. Also, get in touch with some of your local representatives. Bend their ear about things.
I am volunteering with Democrats Abroad – will eventually be helping students studying abroad to vote/register – and making a little good trouble on social media. Honestly just staying somewhat informed is taking up a lot of time. But the turn of events this weekend has me in despair.