How to boost corporation value

I've heard that players can do things to increase or decrease corp value a bit, and am wondering what these things are. In particular, I want to try to skip a few months off an IPO to get some corps privatized faster.

Net profit (not gross) is what figures corporation value. For corporations you control, you can affect this by lowering profit sharing, typically to zero. For corporations in your country, you can lower taxes, also, typically to zero. Remember that in selling your shares, future profit payments will be distributed among share holders based on the percentage of shares owned.