I want to make a search page, offering search functionalities by: 1) word 2) tag 3) category 4) author Can you recommend any technique, any guideline as per how to tackle this?
You'll want to add some radio buttons inside your search form. Then add a filter to your search:
If you'd prefer to let a WordPress plugin handle the work for you, check out Search Everything, in the WordPress plugin repository.
Increases WordPress' default search functionality in three easy steps using Search Everything.
Better WordPress search in three steps
Activate Configure options Search ( maybe that's only two steps )
Options include search highlight, searching pages, excerpts, attachments, drafts, comments and custom fields (metadata).
What it does:
Search Everything increases the ability of the default WordPress Search, options included: