I went heavy industrial and now tht I'm low on cash and low on food should i be sellin military?

Yes. Hopefully you're Communism because that's the only govt that gives your indies a bonus to production. Sell lots of military and buy tech/food. Indy tech primarily, and then other techs.

Xpress markets is 45 mins or less. Sell a chunk of mil at low or market price. Buy some food. Leave enough cash to play a few turns. Set production to whatever is most popular. Sell that and buy some bus/res tech. As Tmac said Commie is the way to go if that is your strat. If you are farmer or whatever you should tear some IC down and focus on your strategy.