Great question. Happy to have a conversation on this (I currently have a reduced launch rate) and explore your options but here are my top tips.
1) Tailor my advice to your business's niche and obviously look in that area, but for example great cofounders could probably be found as follows
- contact MBA students, many want to start their business afterwards
- contact specifically business schools with an entrepreneurship department and mention that you have a careers opportunity - many have contact details of even their careers team
- join entrepreneurship online communities and ask around there
- call up existing businesses in an adjacent space and ask if their leadership wants to become a co-founder
- use LinkedIn to reach out personally to individuals

Happy to find other options together with you. Best of luck, you will succeed.

I had similar issue of finding an ideal person ,until I talked to someone who walked me to a business audition, there are various ways of finding one,but you should consider paying a visit to a business school/University especially during business exhibition and auditions,here you will find more people not only with the required skills but also the knowledge of business oparation and management this will serve as a great deal ,if it does work consider looking for a partner from different backgrounds/are of specialization but with matching skills,or turn to online sites but specifically entrepreneurial ones they will be of help,
Wish you all the best in your search

The key would be to advertise on LinkedIn and research on various platforms such as meetup, and Eventbrite where they will be organising group seminars, webinars, podcast events potentially. You want to attend something where you can see the potential of a candidate, you don't just want to see shiny brand names attached , you want to see either a video of them talking, a podcast, hear or see some sort of presentation, be clear that they know their strategy. How to attack the market, how they'll solve the problems in their niche, how they'll add value how they are upgrading and upscaling. You want to hear their perspective on new markets, competition and trends, and how their navigating challenges like Covid

I can get you connected with a pool of potential applicants. Contact me and let's start some conversations. I would start by getting you connected to a pool of applicants from Babson College and then move to a recruiter based here in the Boston Area.

Hi
How to find a co-founder:
1. Go to networking events - some of which are dedicated to “co-founders dating/matching” - try www.meetup.com for this.
You can also try www.founderdating.com or www.cofounderslab.com or http://www.founders-nation.com or www.founder2be.com
2. Take part in chats in relevant forums (depending on the type of co-founder you’re looking for).
3. Consider joining accelerator/incubator programs for startups/entrepreneurs - some of them connect between founders.
4. Contact head of programs at universities and tell them what you’re looking for. Today, many universities and cities have startup programs with a lot of talented participants (or speakers) who might be the perfect co-founder for you.
5. Talk to friends and family and let them know that you’re looking. This helps expand your network. Post a message on www.LinkedIn.com .

I am a mentor on Startups.com, an international lecturer on entrepreneurship and negotiation, and a commercial startup lawyer. I've successfully helped over 400 entrepreneurs, startups and businesses and I would be happy to help you. When scheduling a call, please send me some background information and the 2 main questions you want answered so that I can prepare in advance (to give you maximum value for your money). My reviews: https://clarity.fm/assafben-david