Annoyed about United, one follows good tip (8)

'tip' is the definition.
(I know that tip can be written as gratuity)

'annoyed about united one follows good' is the wordplay.
I cannot quite see how this works, but
'about' could be 'a' (abbreviation in Chambers) and 'a' is present in the answer.
'united' could be 'u' (abbreviation) and 'u' is found in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'good' could be 'g' (abbreviation) and 'g' is found within the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?