Starting a consultancy firm is not an easy feat.
Even if you have all the industry contacts and you have the skills and expertise to do consulting, getting your first customer to sign a deal would still be a challenge.
1] Exploit specific knowledge gaps.
You need to provide insights and solutions that their in-house employees have no knowledge about.
2] Focus on building relationships instead of getting revenues.
The foundation of any consultancy firm is the business relationships they have accumulated over time.
https://www.justwebworld.com/tips-for-starting-your-own-consultancy-firm/