I'm in the middle of building a very large site based on a very large niche. It doesn't really matter much for amazon, ebay and sites like that because there always going to be here and there.

If you know how to check competition, I would focus on looking at the page authority and backlinks to each page ranking in the top 10.

If you find other niche sites ranking in the top 10, I would say that's a bonus because it just shows that if one affiliate site can rank, then another one can too.

Another thing to look at is the "title" of each page which is ranking. By looking at this, you will be able to see if these sites are actually targeting the "EXACT" keyword your going for, this is also another sign.

I always focus on page authority, backlinks and sometimes domain authority. The lower them numbers, the easier it will be for you to rank "without" backlinks, and that's always my aim.

It's always good to see "answer" sites ranking and forums, it's also a sign of low competition.

Regards

If you see a ton of ecommerce sites like amazon and best buy at the top, it is generally going to be tough to beat them out. Google is obviously favoring these ecommerce type sites for your search, so I would focus on different keywords.

If sites like Amazon are OUT of top 3, better don't even try for a GOOD and SELLING keyword! Google often rank them UP because of the high Authority of the websites and it would be really hard to outrank and even reach Page1 ... But Good Luck!

Big name ecommerce sites will inherently be harder to beat, I would avoid if possible unless you are a true expert.

Maybe you can find longer tail keywords?

I would aim for longer tail keywords, but it seems impossible to find any "buying" keywords with enough monthly searches that also have none of those huge ecommerce sites ranking in the top spots.

So if amazon and best buy are in the top 10 but not in the top 3 spots I shouldn't even attempt? I assumed that meant the particular page just didn't target the keyword very effectively, the page authority is somewhat low, or there aren't many back links to that page. Those big guys mostly rank because of their DA don't they?

My site is going to be based on reviews, so by "buying" keywords I basically just mean keywords based around products (not specific brands obviously). So my intention isn't the same as these big ecommerce sites in the first place. Should I be taking that into consideration as well?