Informational interviews aren't just for college students and recent grads - they're still a fantastic way to research a field or a company. As long as you are just meeting to get information and aren't asking for a job, people are usually willing to say yes to a request if their schedule permits.
Here are my tips for setting up an informational interview:
Send an email or call them
In many industries, voice mail is rather quaint and email is the preferred method of communication. Choose the mode that you guess that person uses the most. Each has its pros and cons.
Unless you already know the person, don't send a text message. It's too familiar.
Mention how you're connected or how you heard about them
Do you have a mutual friend or colleague? Did you hear them speak at a conference? Did you read their blog? Let them know how you discovered them.
Make your request short and specific
Whether you send an email or talk on the phone, say who you are and what you want in just a few sentences. Make it clear you're asking for information only, and suggest a meeting format (phone or coffee) and length (20 minutes is a good start).
Here's an example of how to get started:
"Hi, I'm Steve Jackson and Karen Smith suggested I contact you. I'm a massage therapist and am looking into becoming a hospice nurse. As part of my research I'm contacting some friends of friends who are nurses and asking them questions about how they chose the field and what their work environment is like. I'm wondering if you would be willing to talk with me sometime for about 20 minutes about your experience as a hospice nurse."
Remember that people are busy, so you should allow them plenty of time (for example, two weeks) to get back to you. Don't take it personally if you don't hear from them! There are all kinds of reasons why they are not returning your call or email, and they probably have nothing to do with you.
Use your discretion about how persistent you want to be in following up. If you follow up and then don't hear back and they are a "warm" lead, perhaps your mutual contact can help you connect. If you are contacting them cold, assume they don't have the time and/or are not interested, and move on to someone else.