Here is list of some questions to start you thinking. You will probably come up with some questions of your own.
* Do you want this tattoo to be visible to other people? For some people, a memorial tattoo is a private and personal thing, not to be shared with other people. If you put it on your butt, it will certainly be well-hidden. But is this what you want?
* Do you need this tattoo to be visible to yourself? If you usually wear long-sleeved shirts or sweaters, a discreet tattoo on the inside of your wrist might be good for you.
* How do you want to remember your loved one? The happy times? Or the sad times? Or just their essential character, for good or for ill?
* Tombstone - tombstones, in their various guises, are common in memorial tattoo art
* Name of deceased - the name of your loved one is usually placed withing the tombstone design. However, an alternative is to surround their name with a suitable border, like a border of vines.
* Symbol - instead of directly representing your loved one, you could choose a symbol which best represents them. For example, when you think of them, what comes to mind most readily? A rose? Or maybe a butterfly? Or even a golf club or fishing rod to represent some favourite shared activity or hobby?
* Portrait - some tattoo owners prefer to bear a portrait of their loved one on their body. Do note that portraits are difficult to do. You will want proof that your tattoo artist can manage it. A reasonable alternative might be a caricature. You could ask an artist to draw a caricature of your deceased loved one from a good photo. Pick a photo of your loved one with an expression you want to remember them by.