How to get to a well known company if you don't have any in your portfolio (yet)?

This can be a challenge, but generally once you have one or two, the rest become easier over time. A few approaches to consider:

1. Run analysis to understand who is relevant to the audience you're targeting and would be a hook for them to see. I've worked with social media agencies to look at specific handles for the key contacts I'd like to target to then analyze in aggregate who were the top commonly followed influencers and then worked to book those luminaries/thought leaders/authors to speak at my event. 

2. Check with your C-Suite and who they know that could be a friendly to recruit as a subject matter expert/firestarter. Often times, the approach is to lean into the business solution that your product solves as part of the invite. However, staying more in the thought leadership realm and having your C-Suite lead a conversation on the current top of mind challenges and priorities in the space and positioning the invite to be about learning and networking w/ likeminded peers may help. 

3. Depending on the title you're targeting, it can be relatively easy to hook Directors at large organizations via hospitality, email campaigns, etc. With the executive audience, you could also consider building research and using it as the hook to join and hear the latest to keep pace with the advancements in your space. 

4. Depending on your budget, you may want to start with a balance of third party sponsorships where they will generate the audience for you to ensure you're hooking relevant top companies to start and capturing their contact info to engage later for your proprietary events. 

This largely depends on your event strategy and if it's a mix of audience members across the buyer journey.