Covering the tag up on a caught Fly Ball

[txtrooper]

Hey guys/gals I am new to this site and to Umpiring. I live in the Houston area and have been having a great time Umpiring ASA/USFA Softball games. I am curious to how you work the bases in relation to covering the tag up on a caught fly ball. I have been instructed to buttonhook in on all fly ball situations; although it is hard for me to see the catch/no catch and watch the runners tag up. Another Umpire suggested staying outside the diamond and watching the plate umpire for a signal and then watching the tag up. How do you all execute this mechanic? Any suggestions would be appreciated.