So sorry for your loss. 
Have a look at Bereavement UK - they have "In Remembrance" boards that you can post on.
Other ideas (Taken from what's your grief website
Look at old photos and home videos. Do this alone and have a good cry or reminisce over photo albums with family and friends.
Turn digital photos into a photo album.
Volunteer with a charity or cause close to her heart.
Plan a memorial service or candle light vigil.
Reach out to someone else who knew her by letter, card, phone call, or e-mail.
Host a dinner party / organize a meal out and invite other people who knew her (even if you didn't really know them).
Light a candle for her.
Visit or spend time in a place where you feel close to her - somewhere you went together.
Take the trip / activity you had been planning together.
Read old notes, letters, or e-mails from your friend.
Watch her favorite movie or listen to music that reminds you of her.
Create a new ritual to celebrate the her life. Choose something that can be repeated in the years to come.
Do something she would have enjoyed.
Make a toast or say a prayer or blessing in her honor.
Plant a tree.
I hope these are a little helpful. I'm not religious at all, but I have found going into a church and lighting candles for family members that have died is a very calming thing to do and gives me a quiet moment to think about and remember them.