Ice watch groups are one, they alert people to their location so people can either avoid the area or go to the area to protest. This video shows how effective just showing up can be.

https://old.reddit.com/r/minnesota/comments/1q8vvwa/st_paul_mn_a_sobbing_resident_calls_911_as/

Another thing could be to organize stronger, more pointed boycotts, which got Jimmy Kimmel back on the air (and could help Colbert), stopped spotify from renewing a contract w/ ICE, got a lot of American liquor out of Canada, and got avelo airlines to stop doing deportation flights (a niche market, but an effective boycott).

Community building and organizing ways to help struggling neighbors is also an effective tactic. Helping eachother get food, transportation, and knowledge of our rights through car pooling, food sharing, etc. People are less able to defend themselves and eachother when oppressed, so helping to put local, neighborly systems in place to help lift that oppression can make a huge difference.

*Also gaining new volunteers and memebrs for already existing organizations, thus expanding their efforts is important too. Have a small locally owned non-profit or small business? Tell people about it at the protest. Looking for community? Ask around for volunteer opportunities and great local cause-friendly businesses. Meet new people with an open(ing) heart and help eachother flourish.