Wow. This is great that your site picked up so fast. I am also venturing on the amazon side of things(I am a beginner) and would love to have some insight from you on some things that I am struggling with. It's a long list of question but would really love to have your opinion on these doubts. Pretty Please.
Keyword research
I can't really believe the keyword data very much. I have had some bad luck with this. I have had quite a few keywords(approx:1000 US searches) which ranked in first page of google but never really got any significant traffic whereas I have a couple of keywords that are around 800 searches and are getting me 50 to 100 hits to my site daily and they are ranking in top 5.
So, how low do you go for searches?
Buying keywords
Would you recommend buying keywords like review, cheap, discount, best etc. They seem to have pretty low search estimates
Or would you suggest keywords like For eg: If your niche is parenting, and with a keyword like "should I give my baby X" I write an article and say No, instead give your baby Y and link it to amazon. Also, If you can give X to the baby, then my article takes the shape of "Yes, you can give your baby X, but here are some better alternatives" This sort of strategy is getting me a conversion rate of around 7%. However, my recommended products are in the range of $10 to 30. So, I am not really making much. But, it's a start I want to build on.
Keyword competitiveness
Apart from manually checking it out, I also check with the moz tools keyword difficulty estimate and tend to stay under keyword competiveness of 35. How are you determing competition?
Products
What kind of price range your products are? And how do you link them. Do you just add a text link within the article or image link. Do you link to the products reviews on amazon or directly the buying page. And what kind of words do you use. Do you say directly "Buy it on amazon by clicking this link"
Native shopping ads
Have you tried these?
These are good questions, it means you're actually putting some thought into your actions. I had some of these same exact questions when I was starting out, so I would be happy to help. But please remember that there are multiple ways to do everything, and just because it worked for me does not mean it is the right way/the only way.
Keyword Research
I could write a book on doing keyword research, there's just so many things you can take in account. But at the same time, keyword research can be very simple. There's no magic number that you should shoot for when considering monthly searches, if an item costs $5000 and only has 100 searches a month, I would still focus on that product. 8% of 5k is $400, that's from one sale.
For the most part, the lower the monthly searches, and less focused on "buyer intent", the easier that keyword should be to rank. You want to aim to be #1, you should be satisfied with positions #2-5 (above the fold), and you should be damn hungry at positions #6-13. This is all my opinion. Approx 95% of searches don't look at the second page.
Also, specific keyword research is important, but how those keywords fit into your website, what page they're on, what category they're in, all these things matter. Remember that long-tails are going to be the majority of your traffic, so plan the website for specific keywords and user experience, but include these things into your master plan and "feel" of your website.
Buying Keyword
I wish I could give you an easier answer for this, but I don't have it myself. You seem to be doing pretty well, just remember to answer your visitor's questions in as simple and easy to grasp as possible. Everything is for your visitor.
I think what type of keywords you focus on depends on your specific website and optimization methods. For example, if you have a product review website, then naturally you're going to focus on more buyer oriented terms, and this is why you often see a lot of amazon affiliate websites following this exact method across many websites.
Keyword Competitiveness
I think this this just comes with experience. But first off, I think you're looking at it backwards. I don't ever look to see if a single keyword will be easy to rank, I look at the entire niche as a whole and say to myself, "can I create a better website that those ranking in the top 10"? If I see the same website in the top position, then I look at their articles and overall seo to see if I can compete.
After drowning yourself in the SERPs, you begin to notice patterns associated with quality. Once you sharpen your SEO skills you'll notice good and bad characteristics that in your opinion, will determine the competitiveness of a website and the overall niche.
Products
This is up to you. The more expensive the product, the more hesitant they'll be, the more research they will do, the greater payout you will receive. The more inexpensive the product, the more likely they'll impulse buy, the less research they will do, the lower payout you will receive.
It's up to you, but I would never create a website with the intention of selling a multitude of $20 products, it just doesn't seem worth it to me. But, I'm sure there is someone on this forum, maybe even reading this, that has a website that sells thousands of smallers products a month.
Native Shopping Ads
No I have not.