Use blank lines to separate logically separate parts of a
program. For example, methods should be separated by a blank
line. Also, long blocks of code should be broken into logical
"paragraphs" with blank lines. On the other hand, do not insert
blank lines where they would separate closely related parts of
your code.
Use indentation consistently. Eclipse's format function
(click on Source, then Format) or type
CMD+a to select all and CMD+i to indent (where
CMD is the apple or command key).
Give each declaration and statement its own line. Or,
equivalently, start a new line after a semicolon.
Don't make lines too long (< 80 characters is a good rule)
as they may get truncated or wrapped when printing - making the
code unreadable in either case. You can break a statement over
multiple lines and often make it more readable.