The topic you choose must have enough depth that you can create a lot of content for it. This is important for building an authoritative site, for search engine optimization, and most importantly, for the end user. If you don't have enough content about a topic, you're not going to be taken very seriously as an authority on the topic and it's unlikely you can convince someone to make a purchase from you.
With apps being constantly developed, competent app developers are in high demand. Again, if you have the experience or skills to create successful apps then this could be something you could end up working on as a full-time freelancer. Check out adverts for developers on Toptal, a higher paying jobs site for experienced freelancers wanting to make money online.
The easiest way to find affiliate programs to promote is to check if the people selling products and services you love have an affiliate program – assuming those products and services would be relevant to the visitors to your blog or website. There are also multiple ways to find new quality products or services to promote to your audience based on their interests. You'll find more information on how to do this here.
Tremendeous free teaching, that helps clear the smoke on what it takes to get an online business going. BUT, you concentrated on click bank and said nothing about getting my web site going and all the necessary details. I always thought the web site as a business sign telling people that xyz is open for business, check it out! Otherwise, people would walk and not even knowing that your biz is open. True?