
Can you give a quick overview of SEO and how it works?
I'm struggling to grasp the concept of SEO and how it affects my website (if I had one). Could someone please give me a broad and simple overview so I can understand the big picture and easy ways to improve it?

Quick over view:
On site SEO:
Titles, URL, descriptions, Page content, UX structure, Internal Linking, technical SEO elements ect ect
Off Page SEO:
Backlinks to your website, off site social media shares.
Their are over 3,000 ranking elements from Google, so yeah these are very top level.
Also good information here for the basics - http://moz.com/beginners-guide-to-seo
Is SEO important for your business in simple: YES

While there are many different factors that go into SEO, two of the best ways to break it down is shown below:
ONSITE SEO - Site content, title tags, keywords etc...
OFFSITE SEO - Social media, backlinks, references...
To learn more about the basics of SEO and what's working today, I would also take a look at some of the top SEO forums, Quora threads and also Facebook Groups discussing this topic.

How I breakdown SEO to my clients:
SEO can be broken down into two steps: Optimisation and Authority
1. Optimisation
Optimisation is making sure that Google can understand what keywords you’re targeting, which services and products you sell, and where you sell them.
2. Authority
Authority is making sure that Google knows you have the best content for their users. To grow your website’s authority, you must put out such great and informative content that people naturally share your content and link to your content.
That’s SEO!
Conclusion
That’s how SEO works, in a nutshell of course. It's a lot more complex when you get to the technicality of it and the constant change of the Google Algorithm.
Let me know what you will do with this newfound clarity...

Han Teng, Fixed Income Investment Dealer at AFFIN Group
Wow, thank you so much for the swift answer! :) am going through the link you posted. It's really useful and simple but gets gradually detailed which is even better. Will read more on SEO and hopefully post an article up soon too. thanks again!