This comes under SEO (Search Engine Optimization).
You can do this by add meta tag on your page in the head section :
<meta name="keywords" content="Astrology, Astrologer, .... " />
In the content part you can add words from this your site can be search on net. Or user may enter any word or line for search the related sites.Keywords are separated by comma.
And you can write blog for your website.
Hope this will help you.
And don't forget to mark as answer if it helps. :)