One more tip, this one perhaps more focused on the sales side: find a manager in this big company who will lose his job unless he solves the problem your softwa

One more tip, this one perhaps more focused on the sales side: find a manager in this big company who will lose his job unless he solves the problem your software purports to solve. This is doable, although you need to have a little inside information about the burning problems in the company or industry you want to sell to. Alternatively, find a very senior person in that organization to work as your evangelist, someone who deeply cares about doing the organization doing The Right Thing, and who has the clout to ram things down other senior people's throats. Such people are rare, but might be your only way to get a foot in the door.