A careful choice of a person to ask for letters of recommendation is basically important. Make sure he / she occupies the right position to give you a reference, and the reference will be positive. Letters of recommendation are not less important than your work experience or education. They can either win you a career move-on, or turn you into a loser.
It goes without saying, that you'd better get a person's agreement first and not announce anyone's name before the references are written.
Best Way to Ask
There are several ways to ask: by email, phone or in a private talk. Mind, that in case the person is going to refuse you, it will be easier to make it by email — when say something delicate has to be said, it's always easier done in messages.
The way you ask is also important. Don't put general questions, don't ask alternatively whether you will or you won't get a reference. Be more specific about questioning. Inquire if you seem to be experienced enough and if the person has got time to compose a letter and answer phone calls afterwards. They might be just too busy or unwilling to deal with the letters of recommendation. Be ready to accept it.
In case you get a positive answer from a referee, be ready to provide them with all necessary information: your resume or a CV, your social network profile, a writing sample if needed, etc.
A LinkedIn Reference might also be a need
In general, it's quite easy to get a reference via LinkedIn. Write a message to the person you choose as a referee, ask if they've got enough time to write a letter for you. If something is not clear to you, you can browse the Internet for sample request letters or tips how to get references from LinkedIn.
The Number is Important
As a rule, employers ask for 3 letters of recommendation. It would be nice to have 4, in case someone stays out of touch.
Create a List
Have a list of your referees. Put their names, titles and contacts into the list, print it out and be ready to send it to the employers