Great advice @GailL1 and I would add -- as a person who had several home based businesses -- make sure the location of the home is zoned for business run from a residence. There can be limits or total restrictions on clients or customers coming to the house, including how many a day are allowed, and even if they can park on the street or in a common lot (such as if you are in a condo or apartment complex). And if your business office is in your home but you transact business as a vendor outside of the home -- I'm thinking of crafts people and artists who sell at fairs and farmer's markets, in neighboring towns, etc -- you can be liable for having business licenses not just for the location of your home office but also for every town in which you are physically present for selling. On top of that, you will likely also need a state issued business license. Speaking from experience here.
And even in states that don't have personal state income tax, there is likely state business income tax. Be sure to check all this out because the penalties for not being properly licensed and current on taxes can be severe.
Finally, make sure you have the right professionals to consult with. It's well worth paying an accountant or bookkeeper to set up the list of income and expenses you need to track. Check on the need for malpractice insurance if you give advice of any kind, or on other types of insurance typical for your business type. You might also need to increase homeowner insurance to cover slip and fall type of accidents in bad weather if clients come to you.
Finally, even when doing business primarily over the internet and never seeing customers in person, expect to spend three quarters of your time marketing the business at first. Learn how to attract clients, how to close a sale, how to create sales funnels, referrals and repeat clients.
Having a home based business doesn't escape all these needs. Good luck!
Oh and I forgot to say -- if you are using testimonials on a website to help establish social proof for your business, be sure to be aware of FTC regulations on what a testimonial can claim, and the legal disclaimer that must accompany those. The fine for not following their rules is outrageous.