I'm no SEO expert but since the SEO experts are too egocentric or busy to reply I thought I should give my opinion. So, here is what I consider when assessing the competition of a keyword....
- what websites rank on the 1st page of google. If they are known and powerful websites in their niche I usually don't bother with that keyword. Please note that I'm not talking about websites like wikipedia, pinterest, youtube, facebook, etc. These websites are indeed big, but they're not big brands in a particular niche, they're general websites about everything under the Sun. Amazon might be an exception and I admit that I never know how to treat Amazon, but that's probably because I don't do ecom marketing in general. I mostly focus on informational websites / blogs / autoblogs
- the content of the websites ranking on the 1st page of google. If the top 5 websites ranking on the 1st page of google have at least 2k-3k words, with multiple relevant images and tables and infographics, stats and all that crap (especially if they're big brands or websites with high DA metric) I stay the fuck away from that keyword cause I know that I'll have to create content 24/7 and pour $100s into backlinks to beat those guys. On the other hand, if there is less than 2k words of content and weak sites in general (quora, forums, etc)... or if the URLs of the pages that rank on the 1st page of google are long and ugly I think I have a chance of beating them, and I check the other metrics (the ones below)....
- the RDs (referring domains) of the websites ranking on the 1st page of google;
- the DA of the websites ranking on the 1st page of google;
- the number of keywords and traffic that the websites ranking on the 1st page of google rank for / get;
- the total number of backlinks of the websites ranking on the 1st page of google;
