You could get the ball rolling by getting several pro-South laws passed, such as low or zero protective tariffs, low support of government-sponsored railroads, or other anti-industrial, anti-capitalist (essentially) laws.
It's also important to note that secession was more than just an economic decision; the South felt like it was under moral attack from the North and its abolitionists. If you look at actions and publications from the time, the South adopts a gradually more harsh, even extremist, tone towards the North and abolitionism.
I think in addition to anti-Northern legislation, there needs to be some sort of moral attack that the South makes on the North that "catches on" with Northerners and makes them feel like they need to defend their "way of life" from assault. I don't know what that would be though.