Query Tuning

     I'm hopeing I can get some of you Oracle Experts to enlighten
the unworthy. I've read the SERVER APP. DEV. GUIDE and I know to do the obvious things like querying only on indexed fields and
constraining tables to be joined before joining, but what other general rules have you discovered (and if it's not asking too much, how do they work) for query optimization.  

                                Thanks in Advance
 
                                Jim Harrington