Indirect questions help us to be more formal or polite.

• Could you tell me if/whether + statement word order? (for yes/no questions)
• Could you tell me wh- + statement word order? (for wh- questions)
• Do you know...
• Have you any idea...
• Would you mind telling me...

Interrogative pronouns are used to ask questions.

• who: as a subject/an object, as a pronoun
• which: as a subject/an object, as a pronoun/determiner
• whom: as an object(formal), as a pronoun
• what: as a subject/an object, as a pronoun/determiner
• whose: as a subject/an object, as a pronoun/determiner

http://dictionary.cambridge.org/grammar/british-grammar/pronouns/questions-interrogative-pronouns-what-who https://learnenglish.britishcouncil.org/en/english-grammar/determiners-and-quantifiers/interrogative-determiners-which-and-what

http://www.bbc.co.uk/learningenglish/english/course/lower-intermediate/unit-1/session-2/activity-4

http://www.bbc.co.uk/learningenglish/english/course/lower-intermediate/unit-27/session-2/activity-3

http://www.bbc.co.uk/learningenglish/english/course/towards-advanced/unit-28/session-1

http://www.bbc.co.uk/learningenglish/english/course/lower-intermediate/unit-18/session-2/activity-4

• Can I ask a favour?
• Can you do me a favour?
• Could you do me a favour?
• Could I ask you to do me a favour?
• I was wondering if I could ask you a favour. (indirect question in the past continuous tense)

http://www.bbc.co.uk/worldservice/learningenglish/radio/specials/142_requests_offers/page9.shtml

• Can I + infinitive...?
• Could I + infinitive...?
• Would I be able to + infinitive...?
• Is it OK/alright if I + present simple...?
• Would it be OK/alright if I + present simple(less formal)/past subjunctive...?

• I hope you don't mind me mentioning this but...
• I wondered if we could have a quick chat about...
• Would you mind (not) + gerund...?
• It would be good if you could...

• Would you mind + gerund...?
• Are you OK to + infinitive...?
• Is there any chance you could + infinitive...?
• I would appreciate it if you could...
• It would be great if you could...
• If you could..., that would be great.