There are some question you should ask yourself in the process:
- How is your English?
- What about writing skills?
- Can you entertain readers and keep them interested?
- What do you know about website building, SEO, affiliate?
- How much money you can put in this?
- Do you have a skill?
- Are you good with programming language?
These questions will help you decide what you should do. For example, if you are good at English and has money to put in the project and have some knowledge, you should start building your product. If not you should start with building your website.
Building a website isn't expensive. You can get domain for less than 10$ a year and free blogger blog or use a website here at Wealthy Affiliate. Then, start writing your awesome reviews and sharing your content. The more you write while maintaining quality the greatest the results you will see.
Building an app isn't expensive too. You can build an app and put in-app purchases and adsense ads. And if you are super programmer make a mobile game with in-app purchases and ads.