During one of my talks in the recent past, one young software
professional came up to me and asked whether I would be willing to
introduce a well-known author to him. After speaking with him for a few
minutes I told him that unfortunately I could not make that
introduction as I don’t know what this young professional had to offer
to the author. The person understood the rationale and said he would
come back to me with something compelling. I’ll wait. I didn’t have a
choice here – the gentleman did not provide a strong reason for the
author to meet him.

I think before asking for help, a few things that you should consider:
a) Why should the person help you – what’s in it for them?
b) What does it cost
the person to help you – you may say it’s only a few hours of the
person’s time. Remember that more powerful the person is, more the
premium on his time. You may not have a lot of value for those few
hours but for this person it may be an opportunity cost.
c) Is the help you are asking in the person’s area of strength?
This is important and I think most people assume a lot of things. If
you think carefully and ask for help ONLY in other person’s area of
strengths, the chances are that you will get a quicker and better
response. Also, since this is an area of strength, the person has to
spend very little time to give what you asked.

In summary, whenever you are asking for help, make sure that you are making it easy for them to help you.