The main components in selecting the keywords in SEO Services are relevance and popularity. If you select a keyword that is most relevant but it is never searched then it will also not solve your purpose as your website can not become popular and people can not reach you. On the other hand if the keyword is quite popular but not relevant to the theme what you offer in your website, then you can not have a good conversion. In this case you may have the web traffic but this traffic will not be targeted. So it is necessary to keep a balance between the popularity and relevancy while selecting the appropriate keywords for your website.
There are others factors related with keyword searches. Always keep in mind that keyword searched are based on the age, culture, education and knowledge of the person searching for. The major requirement is to define the target audience and then select the keywords based on these audience. It is generally necessary to create multiple keywords groups in order to target different demographics or audiences.
Keywords should be used in the page title, in the anchor text of internal links, in the filename/URL. You can not ignore the keywords in headings tags (H1, H2). The Meta description tag no doubt contains the keywords as well as it is necessary to use it in the alt tags of images as well as in the page copy. So it is necessary to give attention on the use and selection of keywords as well as implementation of these keywords while offering SEO Services in a website.
Summary
Selection of keywords is the most crucial task in SEO Services. The factors of relevancy and popularity must be taken into consideration. Keyword placement also requires certain rules and regulations keeping in view all the search engine aspects into consideration.