What is SEO? A Complete Guide to Search Engine Optimisation

How Google Works

Google uses automated programmes called "crawlers" or "spiders" to browse the internet, following links from page to page. When a crawler visits your page, it analyses the content and adds it to Google's enormous index — a database of hundreds of billions of web pages.

When a user types a search query, Google's algorithm sifts through its index and ranks pages based on hundreds of factors — relevance, authority, user experience, and freshness — to show the most helpful results.

SEO is the practice of optimising your website so Google's crawlers can easily access it, understand its content, and rank it highly for the searches your target customers make.

The Three Types of SEO

SEO is typically broken into three interconnected disciplines:

Technical SEO — the infrastructure of your website. Page speed, mobile-friendliness, crawlability, secure HTTPS connection, Core Web Vitals, and structured data markup. Technical SEO ensures Google can access and understand your pages.

On-Page SEO — everything on the page itself. Keyword targeting, content quality, title tags, meta descriptions, header structure, internal linking and image optimisation. On-page SEO tells Google what your page is about and why it deserves to rank.

Off-Page SEO — everything outside your website. Primarily link building — earning backlinks from other authoritative websites. Off-page SEO builds your website's authority and trust in Google's eyes.

All three must work together. A technically perfect site with weak content won't rank. Great content on a technically broken site won't be indexed. Strong content and technical SEO without authority won't compete in competitive markets.

Why SEO Matters for Delhi Businesses

Over 80% of purchase decisions in India now begin with an online search. If your business doesn't appear on the first page of Google for the queries your customers use, you are effectively invisible to them — and your competitors who do rank are capturing those leads.

Unlike paid advertising (Google Ads), which stops the moment your budget runs out, SEO builds long-term organic visibility that compounds over time. A page that ranks well today can continue driving traffic for months or years without additional spend.

For Delhi NCR businesses, strong local SEO is particularly valuable — appearing in the Google Map Pack for location-specific searches drives high-intent customers who are nearby and ready to buy.

How to Get Started with SEO

Starting SEO requires four foundational steps:

1. Technical foundation — Ensure your website is fast, mobile-friendly, secure (HTTPS), and free from crawl errors. Use Google Search Console to identify and fix indexation issues.

2. Keyword research — Identify the exact search terms your target customers use. Tools like Google Keyword Planner, SEMrush and Ahrefs reveal search volumes, competition levels and related queries.

3. On-page optimisation — Create and optimise pages targeting your researched keywords. Write comprehensive content that genuinely answers the searcher's question better than competing pages.

4. Link building — Build authoritative backlinks from relevant websites through content marketing, digital PR and legitimate outreach.

SEO requires consistent effort over months — but the compounding returns make it one of the highest-ROI marketing channels available.