When I switch targets between enemies, I use L2+L1. I also use targeting macros.

http://na.finalfantasyxiv.com/lodest...de/ps3/manual/
Cycle Through Enemies (Nearest to Farthest) L2/R2+R1
Cycle Through Enemies (Farthest to Nearest) L2/R2+L1
http://na.finalfantasyxiv.com/lodest.../text_command/
/targetenemy
ALIASES:
　/targetenemy, /tenemy
USAGE:
　/targetenemy

→Targets the closest enemy within a certain radius.

/battletarget
ALIASES:
　/battletarget, /bt
USAGE:
　/battletarget

→Targets the closest enemy within a certain radius that is attacking you.