Amul has sound advice.   I am by no means very knowledgeagle in business start-up but I can tell you some of the mistakes I made with my first try at self employment..my own business.
Sure, I got it all together but wasted some years and personal time and money by not being well enough perpared.

I did not have enough start up capital.  I did not have enough contacts in the industry, locally and nationally, including with financial institutions.  It took me a while untying the mistakes and developing good vendors resources.  I was pretty good at marketing but did not always have the product to market!   This was not a photo business, however, if I had spent a while with a similar company to mine beforehand, a good one, I could have learned enough to have spared some of the hard knocks of those first years.

Again, best wishes.       Tom.