I've been learning how to properly use pronouns and I'd like to know if I've got right idea with these few sentences here...

Please give James and I your undived attention.

Justin and I are going to set a meeting date.

Mom told Dad and her the good news.

Send the letter to Sarah and I.

Subject pronouns: he, she, I, we, they
Non-subject: him, her, me, us, them

it and you are invariable, i.e., used as both subject and non-subject pronouns.

Use the subject pronouns for the subject of a sentence. Use the non-subject pronouns everywhere else.
(The subject is not stated in an imperative, so you won't find a subject pronoun in an imperative sentence!)

Give me your attention. Give James and me your attention.
Send the letter to me. Send the letter to Sarah and me.

Students: Are you brave enough to let our tutors analyse your pronunciation?
So I got them wrong with those two sentences?
Yes, they were wrong in the two sentences CJ listed. Take the other person out of the sentence to see if it should be "I" or "me" and then keep that one when you add the other person back in, as Jim suggests.
1. it should be please give james and me (not I)
it is because the pronoun me is used as an object.

2. number two is correct. it is because I issed as a subject (nominative case).

3. number is correct.

4. send the letter to sarah and me (not I). it is because it is used as and object

I hope this helps!

Teachers: We supply a list of EFL job vacancies
Sentences 2 and 3 are correct.

Sentence 1 should be: Please give James and me your undivided attention.

James and me are the direct object which occur after the verb; therefore, the pronoun should be him, her or me in this case.

Sentence 4 should be: Send the letter to Sarah and me. Sarah and me are the object of the preposition.