Making special time to gather with friends and family, to celebrate your pet's life and say goodbye, can provide some closure around the loss of your pet.
Whether you plan an event while your pet is still with you, or a ceremony after they've passed (or both!), honoring and remembering your life together can help immensely with the healing process.
Irish Wake, Celebration of Life Party, Remembrance Ceremony . . . whatever you call it, it's a time to share stories and photos, food and drink, laughter and tears, and just be together with your loved ones. My friend, Marilou, recounts a beautiful ceremony with Native American traditions in her blog.
These "ceremonies" can be spiritual in nature, or completely secular. Whatever you believe, whatever you want to do, there's no wrong way to celebrate your pet's life.
Your ceremony can also be private - a time you set aside to reflect on your lives together, to gather things that were meaningful to you; perhaps to light a candle, or plant a tree in their memory.
Continuing to celebrate after they're gone can help keep their memory alive. Mark your calendar for the anniversary of their passing, or their birthday, or adoption day, and do something special.