You can’t be perfect so stop worrying about it. Just do your best and whatever you do will be okay. Except, of course, if you intend to hurt someone. That’s not good, so don’t even think about it. But if you’re wanting to build a business on the Internet, then do it.
Build your product. Then put it out there to see if people want to buy it. If they do, then you make the improvements your product needs. Or change it altogether, if it needs it.
If you are writing an ebook, then make sure there are no typos involved. Use your spell check in your program, but also read your work all the way through to make sure you have all the typos corrected. All your sentences correct. All your words correctly used.
And sell the benefits first when selling your product. Benefits sell better because your customers are only interested in what your product can do for them. Customers may not understand the features of your product, (what it’s made up of) but they will always understand what it can do for them.
So get out there and just do it. And enjoy what you’re doing. That’s important, too.