The trick with typesetting ragged right is to be sure you've told the
TeX engine
"make this paragraph ragged, but never too ragged". The
LaTeX \raggedright command (and the corresponding
flushleft environment) has a tendency to miss the
"never" part, and will often create ridiculously short lines, for
some minor benefit later in the paragraph. The Plain TeX version
of the command doesn't suffer this failing, but is rather
conservative: it is loath to create too large a gap at the end of the
line, but in some circumstances (such as where
hyphenation is suppressed) painfully large gaps may
sometimes be required.
Martin Schröder's ragged2e package offers the best of both
worlds: it provides raggedness which is built on the Plain TeX
model, but which is easily configurable. It defines easily-remembered
command (e.g., \RaggedRight) and environment (e.g.,
FlushLeft) names that are simply capitalised
transformations of the LaTeX kernel originals. The documentation
discusses the issues and explains the signficance of the various
parameters of ragged2e's operation.