@nikkielizdemere pulls together a good list of ebooks. IMO a useful list for all types of businesses not just SaaS ones.
My recommendations from the list: 100 Days of Growth, the Copy Hackers books, Hooked and User Onboarding
Good tips. Learning 3: be prepared to respond quickly - yes, very important when in your first baby steps as this can be the difference between life and death.
I disagree with Twitter automation. I have yet to see this kind of tactic work and have a direct impact on revenue. I saw followers grow but not much increase in signups. However - all businesses are different and its easy to setup and test, so experiment yourself. Don't take my word for it ;)