You need to understand what problems they have before you can propose a solution/service/product to them. Also, there's no way to sell unless you have access to these people. If you don't have the network, you need to start growing it first in order to understand their problems and sell to them.

Options (quick brainstorm, you can do better):
1. Look for the 1000 CTOs and 1000 CIOs of each of these companies and figure out a way to get to know them
2. Start off with smaller companies so you can 'level up' and avoid wasting your bullets on the hard-to-get intros in option 1
3. Go to conferences or read online to better understand what problems they have and why its worth hiring the resources you would provide