Two key points.

1)Gooogle's 64 character page title display limit
2) Finding Synonyms and 'Ignored Words'

The 64 Character limit
In organic SERPs from Google, there is a 64 character limit in what it shows in the page title. After that, elipsis are used (...) Best to keep your titles within this limit. This is a soft limit and page titles can be somewhat longer. Other engines, Yahoo, MSN, etc. use longer limits. The actual structure of the tag may want to have the targeted phrase towards the beginning of the tag. This may be somewhat fluid. Use your own style.

Google Synonyms
Don't know if I spelled that correctly - too busy to look it up - but a powerful tool in Google is the synonym locator. It shows you what Google considers as synonmyms. Use the tilde (~) before the word. SERPs list them in bold. These can help locating words Google considers the same as others.