How we change what others think, feel, believe and do
If you want somebody to do something, just ask them.
When asking, maximize your chance of success by being clear and polite. How exactly you do this will depend on the culture and social situation. In many environments the following prefixes can be helpful:
Could you please help me do my homework?
Can you just take me to the airport?
I'd be grateful if you could take the minutes.
It is surprising how often people think they need to use some more complex means of persuasion when simply asking would be enough. Particularly if the request is not too difficult or time-consuming, many people will agree, simply because it is human nature to help. They may also realize that, having helped you, then you will have some obligation to repay the kindness. Promising gratitude makes this explicit.
A clever prefix is to say 'can you', because if they are able, then the logical answer is yes, even if they do not want to do it. Then all you need to say is 'thank you' and they will probably feel obliged to fulfil the request. Of course if they feel deceived there may be repercussions, but at least you have succeeded in the short term.
Saying 'I wonder' is a softer approach where you appear to muse out loud for a moment before asking. When you wonder, you invite other people to join you in finding a solution to your problem.
Other little words can add to the power of the question, such as making the request seem small ('just', 'only') and adding some form of flattery ('you're good at this', 'I know you'll want to be involved here').
Direct Request is the 21st of the 64 compliance-gaining strategies described by Kellerman and Cole.
Kellermann, K. & Cole, T. (1994). Classifying compliance gaining messages: Taxonomic disorder and strategic confusion. Communication Theory, 1, 3-60