The first thing you need and must have to create an informational product is an idea a subject a topic that will fill the needs, solve a problems, or just make life better for some particular and very specific segment of the general population. You are surrounded by ideas if you just look. Look at yourself first. What is your biggest problem? Do your friends share the problem? Are you passionate about a hobby or a sport? These kinds of things are the stuff of which informational products are made of. So the very first thing you need is to identify a topic and, thereby, a market.
Another thing that you need to have in order to create an informational product which will become successful is research. Every topic and every subject are not going to make money. Many of them will but just as many will not. The best research is accomplished by reading and talking to people who have succeeded in niche marketing informational products. Savvy niche marketers can spot a great topic from forty paces with one eye shut. Ask. Read. Research.
When you have an idea and have done the research that has proven that there is a market for your informational product, the rest is just a matter of creating the product building a great website and advertising it.