Keyword is very important for promotion of the website. you have to do keyword analysis according to the theme of your website. you can use Google keyword research tool for keyword research. select long tail keywords according to high search volume and low competition. don't use single keyword, key phrases gives to higher chance to get top ranking.
The one with less competition will be helpful. For example, you have a keyword "abc" and another keyword "abc def" then you should go for "abc def"
It would be easy to give suggestions if you share your website with us.You must do an analysis of what your competitor's are targeting. Look for the trend using Google trends.
In general you should probably choose one semi-competitive keyword as the main keyword for your site and long-tail keywords with low competition for each of your pages/articles.
You should definitely choose less competitive keywords those are getting moderate amount of search volume per month.
We really don't get what you mean, buddy? Before you ask, what is your blog or website's niche and give us more information about it. Once you have a niche for your website or blog, you may need to use keyword research tools that can be searched through Google.
That question can only be answered in full training course in SEO. But let me give some tips. Your selection of keyword depends how much effort you are willing to put in. If you want little effort then for keyword with these: 1: About 1000 to 3000 Searches per month. 2: Some Competition but not too much. Keywords with zero competition are mostly duds. Don't go for them. 3: Some CPC value. Keywords with CPC in low cents are again not worth putting all your effort and time. 4: Broad to Phrase ratio of at least 10. Also, you would need to see the first 10 competitors. If they are giants and don't choose that keyword.