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. 
#2: Another great program is Jon Dykstra's Niche Tycoon. This focuses on paid traffic and outsourcing content to make money with Google Adsense (and similar programs). It requires a bit more of a budget, and also has less of a support community than Wealthy Affiliate, so it's best for people with a bit of online marketing experience and some money to get their business going.
Consider the search volume for your chosen topic. Find out how many people are searching for that topic by running a web search for, say, "quick weight loss." The quotes will make your search specific, so that the only results will be sites that mention the exact phrase "quick weight loss." Your search engine should list the number of search results that turn up for your query. Try to find a topic that turns up fewer than 5,000 results.
Thanks to God I just landed here, I have found someone recommending WA.Actually, am already a free member there, but was just wondering on how to get started.Now i will head back and start over again to see how i will fair on.I am still wallowing here and there, wondering exactly on what I can comfortably do online and be happy with it.Scam Xposer is what has drive me here, since i came across one of Dom’s posts explaining how the guy himself is promoting scam.I have been a victim of scams, one after another, and almost lost hope in this online stuff.
If the answer to each of these questions is a resounding yes, rather than jumping to conclusions immediately, take time to research whether or not others are out there making a sustainable affiliate income from products and content in this niche. In a sense, competition is a good thing here—it'll help you validate your idea and prove that it's worth of building a business around.