Is there anyone who can help me?

Order of words in a question: "Can someone ..."

The secret is: Pronoun before noun

Can Peter help Klaus?

Normal word order. Peter is subject, Klaus is object, so Peter helps Klaus.

Can you help klaus

Still normal word order. Technically pronoun before noun applies, but it doesn't matter anyway. You are subject, Klaus is object, so you help Klaus.

Can you help him?

And again normal word order. As both subject and object are pronouns, everything's fine. Du is subject, him is object, so you help him.

Can Peter help him?
Can Peter help him?

The more natural word order is the latter one. Peter is subject, but the object usually precedes the subject in that case as the pronoun goes before the noun.

And consequently:

Can someone help me?

is better than

Can anyone help me?

which isn't that wrong, though. But be aware that in some cases it feels quite awkward, and in other cases people wouldn't even notice. You may need to develop a certain language feel, I guess.

Important note: This is a tendency, not a strict rule.

As you probably know, someone is an indefinit pronoun, but the rule / tendency mentioned above refers to personal pronoun. So,

Can Peter help someone?

is correct, but

Can Peter help someone?

is not.