Have you ever searched on Google for something and noticed page titles like this:

Car Polish Keywords

Car Polish Keywords

Page titles that load (or stuff) keywords into the title don’t work as well as page titles that use relevant keywords written in a natural way – for readers. You might not notice this effect where there is little or no competition for search results, but it gets a lot more important when you are dealing with competitive keywords.

Google’s Webmaster Quality Guidelines advise:

Don’t load pages with irrelevant keywords.

Google Webmaster Guidelines

This applies in the title as well as in the page body copy.

A good principle to follow is to write natural language titles that include your keywords within the first 60-70 characters. Avoid any temptation to load the title with lots and lots of keywords.

To get more value from your page titles, use the Google AdWords Keyword Tool to research relevant phrases. When you are using this, localise the tool to your country so you can see Local search history, and also change Match Type to Exact rather than Broad if you want to understand exactly what keywords people are searching for.

Choose niche keywords in preference to ‘mega’ keywords – you’ll have more chance of ranking on them initially, and they will help you rank on higher value keywords later.

This excellent video tutorial from Aaron Wall provides detailed instructions on page titles:
Google SEO Friendly Page Titles

This is an article – also from Aaron Wall – that describes the ‘natural language’ issue in more detail:
Search Engine Friendly Copywriting – What Does ‘Write Naturally’ Mean for SEO?

This article from Michael Gray provides excellent detailed guidance on how to prepare page titles, headings and permalinks. Optimizing WordPress Page Titles, Post Titles and Page Slugs.