The following are some suggestions that may help to assist you in your role as a support person.
Facilitating her privacy and a safe environment
Offering her fluids and food
Reminding her to urinate regularly
Giving her physical contact
Massaging her, acupressure
Changing her position
Walking with her
Assisting her to rest between contractions
Breathing with her when she needs guidance
Offering her heat or cold packs, the shower or bath
Communication with her caregiver(s)
Staying calm
Don't complain or place demands on her
Facilitating her privacy and a safe environment
Labouring, and giving birth, is a very intimate, private act, akin to making love. Animals have been shown to stop labouring (or even lose their young) if frequently disturbed while trying to give birth. Privacy does not necessarily mean being alone, but it does mean the woman feeling comfortable with those around her, and having as few 'strangers' coming and going as possible. Women will often unconsciously 'escape' into the toilet, shower or bath to achieve a non-threatening environment, feeling more secure and safe when unobserved.
Think about the type of atmosphere you would like your partner to give birth to your child in. With this in mind, and consider the birthplace you have chosen. You may wish to consider the following:
Lighting. Dimming the lights, you may have candlelight if labouring at home (most hospitals won't allow this due to fire restrictions).
Warmth. Having the room at a comfortable temperature, using fans or heaters, closing windows and doors.
Smells. Burning selected aromatherapy oils (again fire restrictions may limit this to electric burners). Be aware of cigarette smells, burning toast, garlic breath. All these can be off putting in labour for the woman (who usually has a highly sensitive sense of smell). Perhaps some chewing gum or a mouthwash / spray can be handy.
Sounds. Playing her favourite music.