What are some good resources for an engineer who wants to start a SaaS?

Following on the heels of this discussion [1] what other resources would you recommend to an engineer bootstrapping their first SaaS?

I'm about to give it another shot and was really impressed with the linked resource, and it's making me realize there's a ton of stuff out there that would be incredibly helpful – I just don't know where to look to find it.

If you could share some resources or where to look for them that would be incredible. Thank you!

[1]: https://news.ycombinator.com/item?id=23289185