(Photo credit: Kieran Huggins)

Ilya Grigorik of Igvita has put together a great article called 6 Optimization Tips for Ruby MRI. In it, he walks through six different things you can do to improve the performance of your code when running on the regular Ruby interpreter (MRI). For example, interpolation is quicker than concatenation when working with strings, destructive operations prevent wasteful object duplication, and hand-written blocks are a lot faster than Symbol#to_proc.