What you can prepare in advance of day one
There is no bigger leap during your journey as a founder than that very first leap from the safety of employment to the chaos of a startup. I have absolutely no data to back this up, but I would guess that fear of losing the safe monthly income is one of the biggest reasons people don't fulfil their dream to start their own business.
But there are ways to reduce the risk, and even start day one with income, if you start preparing in advance of day one. Notice periods are great for this, but don't tell anyone I said that...
I'll break it down into practical things that you can do to physically get set-up ready for day one, and also commercial things you can line up so that you don't need to take seed investment.
Practical tip #1 - Company registration & bank account
It seems so easy. You can register a company in about 5 minutes now, and we all know how easy opening a bank account is online these days. Well the crucial difference here is that you're opening a business bank account. And despite all the new challenger banks saying how quick and easy it is to open an account, it's not. It will take a week at least.
You don't want to be stressing about this as you approach day one of your new business, so my advice (not that anyone asked) is to get both of these things set-up in plenty of time.
Practical tip #2 - Bookkeeping course
It's possible to hire experienced bookkeepers for a few hours a month to run your accounts, and you definitely should do that once you're up and running. But I think there is real value in doing it yourself for the first 6 months or so. By having to get into the detail of nominal codes and overdue invoices, you will get a much better understanding of the foundation of how your business works.
Practical tip #3 - Personal finances
If no one has warned you yet, please don't shoot the messenger. Your new life as a founder is going to be a bit less easy than before. Most likely you will be taking a much smaller monthly wage from your new startup, or living on savings initially. My suggestion would be to trim back your personal monthly expenditures as far as possible ready for day one. The fancy gym, the daily latte, the 74 online TV subscriptions etc. By going absolutely bare minimum on day one, it allows you to take less out of your new business, but also allows you to start adding little luxuries back in as the business hits some early milestones. Much better for morale than constantly having to take more things away bit by bit.
This was 3 months into running Molzi. I was able to be fairly relaxed from day one by making sure I had clients lined up ready to go.
Commercial tip #1 - Start networking
You really can't start this too early. Ideally it would start a year or so before you go it alone, but even a few months is good. Start connecting on LinkedIn with people that could give you value and could get value from you in your new startup life. But don't start trying to sell to these people, that can come in the future once you've started to build a relationship through sharing your thoughts on LinkedIn, or commenting on their posts. I would suggest sending connection requests with a short message like "Hey, I'm planning to set-up a new business in the next few months and would love to connect to learn from your experience". Something like that, an ego-fluffer. You may find yourself getting advice or opportunities without having to ask for them.
Commercial tip #2 - Ask potential clients for help
You will have some kind of idea of what your product or service is going to be. And I have no doubt that you think it's great, but do your potential clients agree? Well, why not ask them. While running my business, most of our new product development came from asking potential clients that we didn't even work with what they thought of our ideas. We would develop the proposition with them and more often than not, it lead to them hiring us.
Again, a cheeky LinkedIn connection with a message like "Hey, I'm launching a new X service and wondered if you had 5 mins free at some point to give me your feedback". Again, you're not selling, but you are. You're showing them your service but without the pressure on either side to commit. And the best thing is anything they don't like about it you can change, and then it's pretty difficult for them to say no.
Commercial tip #3 - Sign a first client
Super important. You don't need to start your business/quit your job until you've signed your first client. Just because you planned to do it on 1st June doesn't mean you can't push back to 1st September if it means you start day one with a paying client. Most clients would never expect to start working with a business straight away, so just build in a leadtime that matches your notice period so you can reduce the risk further of starting the business without testing the proposition and having a customer.
Hopefully some of them are useful if you're thinking of making the jump into self employment. Notice that I didn't mention a shiny website or polished pitch deck. Not important for day one. Especially as your product proposition is likely to change about 20 times in the first few weeks, each time you take on customer feedback.
Good luck and let me know how you get on!