In the mid ’70’s I met a lady who had an extraordinary shell collection in addition to a basement filled with labeled boxes of more shells as this was her business.
I became interested enough to acquire a few specimens without breaking the bank (not hard to do if you wanted some prime quality rarity), since the range in prices varied tremendously.
Of course my interest was as a photographer, so after I shared some of my results with her and thereby had “proven” myself, I was granted access to her amazing collection as well. (Even had a few images published in one of R. Tucker Abbott’s books, Seashells, 1976).
While I haven’t done this kind of work in many years, my approach today would be no different: 1) Eyeball my subject closely trying to find a position that reveals it in an exciting and revealing way. 2) Find a compatible background that isn’t distracting (you’ve always got your black velveteen, but it’s often more interesting to go beyond that). As described in “Flower Power,” the appropriate sized piece of “Aquarium” coral, spray-painted matte black, makes an excellent background. 3) Be aware of the light (for what it’s worth, all these were done with natural light). 4) Apply proper technique (tripod, macro-lens or setting, smallest f/stop for maximum depth-of-field — if that’s your thing — maybe polarizing filter to minimize glare on the shiny ones, etc., etc.). Basic stuff. You should know the drill by now.
Finally, keep in mind because of their designs and formation many shells lend themselves to “Konfabulation” (Mirror-image blending: “Seeing Old Work with New Eyes”). Two examples here: “Chambered Nautilus” and “Murex pectin” Konfabulations.