Choosing who to contact at a giant corporation

Get a connection, someone that knows someone high up. This is what places like LinkedIn are great for.

Also, make introductions at places like trade shows and gather business cards for cheap freebies. People that give away their business card at these settings understand your goals, but don't be surprised if they never respond to you after getting a $1 usb drive.

Blindly contacting someone high up at the company will quickly be met by a gate keeper that is skilled at keeping uninvited sales pitches away.

I was in your positions a few years ago. My experiences tell that it is useless to try to contact important people that you mention. Important people only want to meet important people. That's what I see.

Good connection is important in this condition. But you don't have to meet these important people to make the company to be your client. If you are sure that your products/services will give more benefit to the company, then you will find the way.

You can start by coming to their front office and tell your purpose. Maybe the chance is little, but you won't know the result if you don't try it.

Another option, you can use the 'backdoor'. I mean you have to do some research, for example, to find out where are they usually having a lunch time. If you found it, then you can start networking with people who works there.

And if timing is right, then you can start telling your purpose or etc.

Although it sounds unlikely I've had success simply by guessing the relevant email, typically firstname.lastname@company.com and sending a note along the lines of 'apologies for the cold email but there was not other way to get through..from your views here / role in X etc.. I thought this would be of interest. Obviously this is basically spam so please only target very relevant people who might actually be interested but are otherwise blocked by gate keepers.