As Sara wrote, you have to define your target group. This is always the very first question I ask the startups that approach me because this is THE element that generates all the rest, from the product or service you offer, to the message you will be using to reach out to the target group and the best tool to use to advertise to them.
You have a corporate business, so you need to define first your target group.
You say Large Corporate companies?
I say Be more specific: who is the person in the company X taking the final decision? Base on what or whom? You might end up with 2 target groups: the person taking the decision and their influencers.

Only then you can work on the right message and medium to reach out to them.

I'm currently coaching 5 startups and doing a very similar work with them. Give me a call and we can quickly define your target groups and how to convert them in clients :)