What should you do?
Here's one trick: Open up a newspaper or go online to a news site and look at the people in the news stories. As you look at each person or read their name, ask yourself – does this person know what I know about “X?” In almost every case the answer is a resounding “no.” See? You are an expert, you know more than 97% of people out there on your topic, and you need to stop doubting yourself and just get back to work.
Remember to follow your outline. If you find yourself diverging from the outline, change the outline to see if your new track is going to work. If it's not, go back to the original outline.
Let's say you're writing about how to grow organic vegetables on tiny pieces of land. You find yourself writing an unexpected chapter on a method that isn't compatible with organic gardening – does it fit in your outline? Doubtful. It might work in a non-organic info product, and so you set it aside for another time. But what if the new chapter is on growing organic flowers? You might place that somewhere in your outline, perhaps near the end. Or it might become an entirely separate bonus.
Add graphs, pictures, and illustrations anywhere it will help to illustrate what you're teaching. It's just easier for people to learn when they can see what you're talking about. Plus good visuals work just like a headline, in that it grabs attention and gets people reading. So don't be afraid to use plenty of visuals so long as each one helps in conveying what you want to say.
Edit your product. If you can, when you're done writing you should set it aside for 24 – 48 hours and then come back and edit it. As you read it, look for anything that might be difficult to understand and either reword it or elaborate on the point to make it crystal clear. Any language that is confusing should be eliminated. And if you've found that you rambled on about something irrelevant, by all means, get rid of it.
Tips for editing: Imagine you're the intended audience reading your work for the first time. Would the reader understand what you're saying? Would they be riveted or bored? Is there stuff missing?
Trim long sentences to 25 words or less. Lose the long words and phrases and replace them with short, to the point words. Break up your text into small, manageable pieces with spaces in between.
Choose a layout for your ebook. Entire books have been written simply on how to layout a book, so instead of trying to cover it here, I'm going to refer you to an expertly written article for some free advice... http://www.thatscreativeebookdesign.com/design-and-layout-of-your-ebook
Go into Beta. That is, choose a small handful of people to show your book to, and get their feedback. Also, do another read-through and look for typos and changes you want to make. Based on the feedback, make any necessary changes.
Sit back. Relax. You've just created a killer info product.
Don't relax for long – now it's time to get it into the marketplace. Write your sales letter, add bonuses, contact affiliates, email your list – you know the drill.
Rinse and repeat. Every time you make an info product it should get a little bit easier because you've done it before. In fact, don't be surprised if product ideas start popping up everywhere – you are, after all, now a bonafide product creator!