Dave's right. Lots of planning is your key. And he's also right about vectors. You can make them as tiny as you want; they're vectors you can scale them up until they're as big as God Himself and they'll still be crisp and clean.
I found a tutorial that you might find useful as well. It was posted about four years ago when the growing things were really popular:
http://library.creativecow.net/articles/hansen_jaysen/growing.php
- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')
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