Website ideas for your site should come from what you are familiar with or know very well. Everyone knows something that other people are interested in. However, when coming up with a subject for a website, the subject must be one where it would be possible to generate significant traffic to your site, and at the same time not be such a big topic that your site will never see any traffic because of the competition.
To compete with Amazon.com or Monster.com would be very difficult,and
may require a lot of advertising revenue. The sites that are
best to break into and obtain significant traffic are niche sites.
are sites unlike the huge company sites that have huge advertising
budgets, but are aimed at a particular
A niche site idea may be your occupation. For example, if you a tax accountant, maybe a site about tax accounting would work for you. Or, if you know how to fix refrigerators, maybe that would be a good idea.
You should select a handful of ideas and then determine which of these ideas will work best on the web. The ones that will work best for you depend on the user interest, the number of sites already supplying this information, and how well you know your subject. If you know little about the subject, but are willing to do research, that may work for you. However, it really helps if you have passion about your site. Find something that you can write about easily, or something that you really want to learn and research and can be passionate about.
There is a website builder and instructions that will walk you through this process step-by-step and help you make the right decision. It has tools and information available to find out the supply and demand for your ideas. Take a look at what I use to create successful websites at SiteBuildIt