In most American cities, real estate and development companies own the city council and mayor (if there is one) thoroughly. Yet people like Kshama Sawant have managed to get on the local government and make effective changes. Any socialist electoralist strategy in America has to successful start at the local level, so I'm asking if there's any stratagies we should employ to build labor power and/or effect local legislation. Of course direct action strategies like the Young Lords did in the 60s is effective, but I am thinking more electorally here. Direct action and electoralism can, and should, be in concert.
It's going to depend heavily on what your municipalities can legally do. A number of DSA chapters have run into this issue where they've been successful in local politics only to have the state legislature overrule whatever they achieve. Read your state constitution and city charter for more information.
If you're state allows municipalities a lot of autonomy though, then you've got to build a party and win a majority of seats (and possibly the mayoralty, read your charter). Maybe you can run referendum, or sneak in something in the off cycle elections, but that's how to control local government. The good news is that you can make the local officials' lives hell in the meantime.
Edit: In most cases it will be best to attack state house seats. In most Democratic controlled states, a dozen or so house seats held by a left coalition would be enough to block any Democratic legislation, then you try to extract concessions from them. Not exactly a revolution but it might be something.