The web like a giant subway map: each page/document is a “stop,” and links between pages form the network. Search engines crawl these links to find pages and then index them.
SEO has two main roles:
Crawling & Indexing — allowing search engines to discover and store pages
Ranking / Serving Relevant Pages — deciding which pages to show for a given query and in what order
SEO is a balancing act: relevance (how well content matches a query) and popularity (how much authority/endorsement a page has) drive rankings.
How Search Engines Work & Key Concepts
Crawling & Indexing
Search engines use bots (“crawlers” / “spiders”) to follow links and discover pages.
Once a page is found, the engine processes the page’s content (text, images, code) and stores it in a massive index for future retrieval.
Technical issues can block crawling or indexing:
Incorrect robots.txt rules
Pages hidden behind forms or login walls
Duplicate content
Links deeply buried or inside frames/iframes
Relevance & Popularity (Ranking Factors)
Engines use many signals (hundreds) to assess whether a page is relevant to a query and how “valuable” or trustworthy it is.
Relevance is more than matching keywords; it includes semantics, context, user intent.
Popularity is often inferred via links (how many pages link to it, how authoritative, anchor text, etc.).
Search engines assume that more popular pages tend to be more trustworthy (though this is moderated by other signals).
SEO Best Practices & Strategies
For Users & Search Engines
Build sites for users, not just for search engines (i.e. readable, navigable, useful).
Avoid cloaking (i.e. showing different content to search engines vs users).
Every page should be accessible through some static text link (so crawlers can reach it).
Keyword Usage & Targeting
Keywords remain the foundation of how search queries are matched to pages.
But “keyword stuffing” (overusing keywords unnaturally) is harmful and outdated.
Best practices for use of keywords include:
Use in the title tag (preferably near the beginning)
Naturally within the body text (and variations)
In image alt attributes
In the URL
In the meta description (though meta description doesn’t help ranking directly, it may improve click-through)
Keyword density is no longer a reliable indicator for ranking; modern algorithms look at context, co-occurrence, semantic meaning, not raw density.
On-Page Optimization
Title Tags:
Keep them concise (first ~65–75 characters are likely to show)
Place important keywords near the front
Optionally include your brand name (often at the end)
Meta Tags / Robots Tags:
meta robots (index / noindex, follow / nofollow) to control crawling/indexing of specific pages
nosnippet, noarchive etc. to control whether the snippet or cache show up
meta description serves as ad copy for the search listing (not a ranking signal)
URL Structure:
URLs should be descriptive but concise
Use hyphens to separate words
Avoid excessively long dynamic query strings
If possible, include your target keyword in the URL
Use canonicalization (or 301 redirects) to handle duplicate content or multiple URL versions pointing to the same content
Canonical Tags & Duplicate Content:
Multiple URLs with the same content confuse search engines (which one should rank?)
Use <link rel="canonical" href="master-URL"> to tell engines which is the “preferred” version
Or use 301 redirects to consolidate duplicates
Structured Data / Rich Snippets:
Use schema.org markup (or similar) to help search engines understand specific content types (events, reviews, products, etc.)
Rich snippets can show extra information (stars, images) in search results, improving click-through rates.
Link Building & External Signals
Links (inbound from other sites) remain one of the strongest “popularity” signals.
But not all links are equal. Quality, relevance, anchor text, domain authority, and context matter.
Effective link-building strategies include:
Earning links through valuable, shareable content (“linkbait”)
Networking / outreach to relevant sites
Getting customers or partners to link back to you
Being newsworthy / creating PR-worthy content
Be careful about paid links or link schemes — search engines (especially Google) may penalize sites doing this.
Usability, User Experience & Engagement
Search engines increasingly use (or infer) signals about user satisfaction:
How long users stay on your page (dwell time)
Bounce and return-to-SERP rates
How often people share, bookmark, or return to your content
High-quality UX helps in multiple ways: better retention, more shares, more natural backlinks.
The idea: “No one likes to link to a crummy site.”
Keyword Research & The Long Tail
It’s not just about high-volume keywords; many “long tail” queries (more specific, less searched) cumulatively make up a large portion of traffic.
Long tail queries often lead to stronger conversion, since they tend to reflect more specific intent.
Use tools like Google Keyword Planner, Google Trends, Bing Ads tools, and others to find keyword ideas, search volumes, and competition.
Also estimate “difficulty” (i.e. how hard it is to rank) before choosing target keywords.
Measuring, Monitoring & Adjusting
Metrics to track:
Search traffic (how much of your site traffic comes from search)
Search engine referrals (which engines are sending traffic)
Keyword performance (which queries bring traffic)
Backlinks / linking domains
Engagement metrics (time on page, bounce rates, etc.)
Watch for sudden drops in traffic or rankings — possible causes: technical issues, penalties, changes in algorithm, content removal.
Use Webmaster Tools / Search Console (Google, Bing) to see crawl stats, indexing, errors, and submit sitemaps.
Be patient — SEO is a long-term endeavor. Changes may take weeks or months to show results.
Misconceptions & Things That Don’t Help (or Can Hurt)
Search engine submission (i.e., using a form to “submit your site”) is mostly obsolete — search engines find pages via links/crawling anyway.
Meta keywords tag is no longer used / ignored by modern engines.
Keyword density is largely irrelevant now. Overemphasis on it is misguided.
Paid search / ads do not directly boost organic rankings (though ads can help indirectly via traffic/exposure).
Don’t panic over small ranking fluctuations — rankings fluctuate naturally. Only major, sustained drops usually merit investigation.
