Oh, man. Again...it can be really hard to narrow it down.
There are so many incredible resources for freelancers made available today—way more than when I started freelancing over a decade ago. Freelance to Founder is part of a larger blog for freelancers we manage called Millo. At Millo, my team and I try to keep this running list of tools for freelancers updated and accurate with only the best tools we’ve found and used. We also constantly update this list of freelance job sites for freelancers who need to find clients fast.
In addition to that, I’d recommend you read/watch content from Sean McCabe, Brennan Dunn, and Ryan Robinson, among others. As well as follow companies like AndCo, Freshbooks, and Bonsai for the latest trends and developments in freelancing.
I also believe accountability is a HUGE factor when you're working for yourself. There are a few communities I'd recommend looking into. For example, we've got a free Facebook Group called Millo Mastermind. There are also a couple Slack communities for freelancers (here and here) I'm a part of that really pay off.
Of course, there are conversations happening around business and freelancing here on Cake as well that I can't wait to dive into. 😃