Hi all!
This is a really stupidly basic question, but it occurred to me that I cannot remember how to politely, or formally, say "how can I help you?" in Irish. Is "cad atá uait?" acceptable? It strikes me as very direct, but "an bhfuil aon rud a bhfuil mé ábalta cabhair a thabhairt?" seems convoluted and unnatural. Any ideas?

Maybe:
An féidir liom a bheith úsáideach duit?

or:
An féidir liom cuidiú leat?

or:
An féidir liom cúnamh a thabhairt duit?

Wait for more suggestions.

All that Ade said

An féidir liom...
Or
An bhfeadfainn ...

After the introduction you can say if appropriate Céard/Cad atá uait? When said in the right context and tone of voice I don't think it's rude.
But if you said it as soon as somebody walks in the door then like in English (What do you want?) then it wouldn't sound well.

Another option:
Ar mhaith leat cabhair?

If showing somebody something like in a shop:
Ar mhaith leat é seo?
An dtaithnaíonn sé seo leat?

Like in English there are loads of different ways to phrase it.