Present your girlfriend with a short note or card telling her how sorry you are for her loss and that you will always be there to support her. Because the purpose of this letter is to cheer her up, keep the sentiment positive and lighthearted, rather than focus on the sadness of the occasion. Use your own judgement on how humorous the tone of your sentiment should be, as each woman handles her grief in a different manner.

Invite your girlfriend over for a special dinner to take her mind off of her grandmother's passing for one evening. You aren't ignoring the situation by doing this, you are simply giving her a few minutes to be happy in the midst of sadness. Bring in her favorite food from the restaurant where you shared your first date or make a pizza together. Regardless of the type of food, she will appreciate the pleasant distraction.

Send your girlfriend a small gift to show her you support and love her. Choose a cheerful and brightly-colored bouquet of flowers or a box of chocolates she can eat when she is feeling especially upset. A small stuffed animal may make her smile and give her the feeling you are there to comfort her even if you can't be physically present.

Create a relaxing spa night at home. During this emotional time, she likely needs a bit of alone time to rejuvenate and many women find pleasure in pampering themselves. Turn down the lights and play relaxing music to mimic a spa experience. Purchase a home manicure or pedicure set and place it by a bathtub filled with warm water so she can do her nails. After she is finished, offer to give her a back, shoulder or foot massage. According to the Mayo Clinic, a massage can help give comfort and reduce anxiety.