I think the lighting, composition, etc. are good in these pictures, but it doesn't look genuinely macabre. For one thing, you seem to be implying that the skull was hacked out of some animal's head, yet it's completely clean. There's not a spot of blood on it. I suppose it could have been washed off after being removed from the bloody mess, but what's the fun in that? You need to be messier. It needs to have stains, blood, and bits of muscle-looking stuff all over it. Not necessarily to the extent that it's swimming in gore, but enough so that it doesn't look like a butcher just happened to place a sort-of-bloody knife next to a random skull. Also, I can tell that the stuff on the knife is made of strawberries or some other fruit... Gotta find better supplies to make a mix. You could try using real raw meat and dipping it in watered down, dark red paint or something. If you're worried about getting your props too dirty, then you can't really do macabre. Macabre is all about death, decay, rotting, gore, etc. Without that, it's just a bunch of random props sitting on a table. I realize you might have been on a time crunch because it was an assignment, but if you really want to get into this genre, take your time with it and go all out. Even if you have to let stuff soak in bowls of fake blood and risk permanently staining your props, it'll be worth it if you get some good shots. All in all, you've got the right idea, but you need to make the gore more realistic to achieve a true "macabre" feel. As for your table situation, try looking for something thicker than a sheet of plexi-glass. I realize most good materials are expensive, but if you're creative and look in the right places, you never know what you'll find. Even cheap stores like Wal-Mart might have something you can use. Just keep looking. Good luck.