30mm + Jewelry. HELP!

Hi all. I'm still getting to know my camera, and I'm a bit of a newb. I'm trying to take pictures of jewelry (on mannequin + alone), but my pictures aren't coming out nice.

1. During the day, with natural light - they come out grainy and blurry, and overall quality is not good. No matter what I do, the lighting is dark and my pictures look worse than camera phone pictures.

2. During the evening, with a "soft light" (warm light) lamp - they come out with better lighting, but still blurry.

I'm at wit's end here. During the day, I've tried taking the photos in all different parts of my room, in different angles. During the evening, I've tried taking with the light angled at different places.

Nothing works! I've read up on this, and I've tried different ISO settings and aperture settings, etc, but nothing is working. I'm currently on a SUPER tight budget so I have to stick with this 30mm lens, but does anyone have any advice or suggestions on how I can take good pictures? Many thanks in advance.