I've been a solo-founder multiple times (a couple quite successful). There are lots of advantages of being a solo founder, but there are also a number of struggles. The biggest struggle bus I seemed to always be on is the loneliness or isolation which is how I describe it. When you have a co-founder the isolation is still there, but you have someone to share it with, which helps you motivate each other and push each other.
For me, to overcome that isolation, I found that I had to engage people in the industry more, engage with activities and people that I feel were reasons I started. This helped me fight the isolation. Another good side affect of doing this is that I was able to meet more customers, engage them directly and use that to help me not feel so isolated.
I also feel finding someone you can turn to and just vent that understands you are not fatalistic but have to vent so you can get it out of your head to refocus is critical. Sometimes you get 2 people, one too vent to like that, and one who can mentor you in the business aspects. I am lucky that I had a mentor that would/could do both, and he has the credibility on business.
Today I have more than one mentor but for different things. I am also not a founder currently but it is only a matter of time before I start something new. And given my past, there is a high likelihood I will be solo again unless I just ran into the right co-founder.
Option A: Get married. Your spouse is now your co-founder, gets a 50% share, and is invested in your success. This is the path nearly all great "solo" founders go, but it can end in divorce, because that's the only exit.
Option B: Find your #1 fan. Just tell random people about what you're doing. Someone out there will be a fanatic who gets excited about every update. Some might even propose things or offer resources to help. Sometimes you can promote them to a cofounder (mine started at 0% then 5% then 15% equity). It might seem like a bit, but the moral support can be surprisingly powerful.
Option C: Promote a hardcore employee. At some point you'll get employees who really believe in the vision, sometimes even more so than the founder. This seems to be the second most popular support pillar for solo founders.
For me, to overcome that isolation, I found that I had to engage people in the industry more, engage with activities and people that I feel were reasons I started. This helped me fight the isolation. Another good side affect of doing this is that I was able to meet more customers, engage them directly and use that to help me not feel so isolated.
I also feel finding someone you can turn to and just vent that understands you are not fatalistic but have to vent so you can get it out of your head to refocus is critical. Sometimes you get 2 people, one too vent to like that, and one who can mentor you in the business aspects. I am lucky that I had a mentor that would/could do both, and he has the credibility on business.
Today I have more than one mentor but for different things. I am also not a founder currently but it is only a matter of time before I start something new. And given my past, there is a high likelihood I will be solo again unless I just ran into the right co-founder.