Sorry I don't agree with you as for as general procedure to drop datafile is concerned with:
Don't do/make a habbit (no matter tablespae has data/not) what rpardip suggested for god sake if you are in archive log mode. You might be at work whole night if you have data in the datafile. You can't bring back your tablespace online. it asks for recovery. Best is export contents of tablespace and then offline and drop, and rebuild the one you dropped.
DROP TABLESPACE xyz OFFLINE INCLUDING CONTENTS ;
General reminder, what we tend to do in hurry in day-to-day life. A big lesson I learned from it being at work 36 hours, unfortunately I didn't have good backup either.
The ALTER DATABASE DATAFILE <datafile name> OFFLINE DROP command, is not meant to allow you to remove a datafile. What the command really means is that you are offlining the datafile with the intention of dropping the tablespace.