What does this sentence mean:“If you fail to dot an “I” or cross a “T,” you could be…”? [duplicate]

Question

Possible Duplicate:
“there are still a few administrative i's to dot and t's to cross”

From here there is a sentence:

If you fail to dot an “I” or cross a “T,” you could be banging your head against the wall for hours.

What does the author mean by dot an "I" or cross a "T"?

Thanks.

It's actually a lower case i that gets dotted, if that helps in your understanding. As Barrie explains, it means taking care of the minutest of details, like the dots on the "i"s and the crosses on the "t"s.
Related: the advice (to Americans) to be very careful in filling out their (federal) income tax forms, because "the IRS will drive a Sherman tank through a pin-hole".

Barrie England · Accepted Answer · 2012-04-08 19:25:25Z

up vote 1 down vote accepted

It means to be meticulously accurate in what you are doing.

answered Apr 8 '12 at 19:25

Barrie England
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marked as duplicate by RegDwighт♦ Apr 8 '12 at 19:58