These are settings I found most helpful (start with Window > Preferences):
> Java > Code Style > Organize Imports > Number of static imports needed for .* (e.g. java.lang.Math.*): 1
Setting this to one prevents eclipse from messing up deliberately chosen static imports.
> Java > Editor > Syntax Coloring > Java > Type Variables > Enable [x]
(Choose bold and a good color e.g. cyan blue)
This allows one to use reasonable type variables, e.g. class Entity<Id> or MyMap<Key, Value>
instead of only non-descript single-letter type variables without confusing them for actual types.
> General > Editor > Text-Editor > Show whitespaces characters [x]
(Choose tab, space and ideographic space, disable breaks).
This allows you to see if tabs/spaces are wrong and if there are superfluos trailing chars and allows you to see if empty lines indented properly. This is mostly an OCD code-style thing of mine, I have an unfortunately complusory need for it to be clean.