Pre-Panda, you could make huge amounts of money, from just Adsense ads slapped up on your site. But since 2012 (Post-Panda), income from ads alone is close to impossible for MOST blogs and sites, with only the super big, very old ones (think the ones 10 to 20 years old) being the only ones today still living off ad views/clicks aone.
The bulk of my income is of course sales of my books and art. I'm an author of Epic Fantasy (main character is an Elf wizard with his unicorn; 130+ novels and 2,000+ short stories in the series which first started in 1978 - next year will be it's 40th anniversary), am an artist (watercolour, acrylics), art car builder, costume designer, CosPlayer, YouTuber (vlogger and gamer) and doll maker.
Income from my blog is as follows (in order from top/most to bottom/least income):
Having a product, especially a none-affiliate, original unique to you product that you created yourself, is definatly the way to go.
No. I don't do product reviews. I've done a few over the years (maybe 10 at most since 1997) but review writing just wasn't my thing.
My advice is to find something you are passionate about in your everyday life: Fishing? Doll making? Collecting coins? Playing Magic the Gathering or Dungeons and Dragons? Cooking? Auto detailing? Painting watercolor? Road trips in an RV? Listening to music?
Answer this question:
What do you do for fun?
What are you happiest doing?
If you had endless cash and was free to do anything, what would you do?"
It doesn't matter what you do in your spare time, whatever it is, THAT is the topic you should write about on your site/blog.
I have a friend who's income is 100% from Amazon Affiliates. Do you know what he does? He enjoys restoring antique camper trailers. So he writes a blog about restoring antique camper trailers.
The blog post that brings in the bulk of his income, is a how-to article, on how to coat your RV's roof with rubberized coating. The article has lots of photos (taken by his wife) of him repairing the RV roof.
At the bottom of the page, he links to the products he used: the liquid rubber, the roller brush, the seam sealing tape, etc. via Amazon.
The liquid rubber he uses is $300 a gallon and it takes about 5 to 10 gallons per roof. He earned 20% from Amazon on those sales, meaning he makes at minimum $300 and up to $600 or more every time someone buys that liquid rubber (300x5=$1,500x20%=$300)
I know another guy who is a plumber and writes a how-to blog for unclogging toilets. He monetizes with links to plungers and drain cleaners.
I'm an author. I write articles on the following topics:
And so, at the bottom of each page, you find links to my own novels on Amazon, in addition to various how to write books by other authors.
The point is, it doesn't matter what the topic is, as long as it is something that YOU enjoy doing and can share your knowledge of with others. And no matter what it is, you can always find affiliate programs to match it.
So don't go looking for a "top" affiliate and try to write for them... no!
Instead, look deep inside yourself, to find out what things you do every day, that you love doing, and write about those things, then seek out the affiliates that match it.
Yes I can.
If you pay attention to each of those articles, you notice affiliate banner image links in various places on the page, some in the sidebar and others in the body of the text
Hope that helps. Good luck!