Insert your opening tool in the seam, starting at the top.

You could start at the side or the bottom, but you may find that the shell may be harder to pry apart.

If you're only using an opening tool:

Use the tool to undo clips located in these areas.

If you're using both an opening tool and pick:

Use the tool to open a gap small enough that you can slide a pick into

and slide it around the side to undo clips located in these areas.