1. Learn industry condition
Search the main keywords of this industry, the first 5 search result pages can basically summarized condition of the industry. For example: the keyword "SEO", the first 50 sites are basically very professional, and most of them are main domain name, the majority domain name contain SEO.
The first 10 sites in search results of this industry keyword, are they mainly auction site? business site? corporate website or personal website? If the majority are auction sites and industry sites, then more commercial value of the keyword; if more personal website, most of the industry uses advertising alliance forms, may consider innovative profit model; simple corporate website, then the competition is not strong.
From these, you can generally know the industry condition. Similarly, you can learn about the building materials industry, the weight loss industry, tourism industry, non-ferrous metals, filters and other industries.
2. Collect industry keywords
Search the industry main keyword, click more relevant searches on the bottom of the first page of search results. Get more industry keywords from here, make an appropriate selection.
You can use Google Adwords to get the search volume per month for each keywords.
3. Analyze keyword competition
Choose the keywords that fit you from the industry keywords collection. Including: keyword relevance, keyword search volume, keyword commercial value.
As for the selected keywords (we call second level keyword), learn about second level keywords rankings condition with the same way of learning about industry situation.