Here's a few suggestions i have in mind.

It's quite apparent that this is your first texture pack and i congratulate you for trying and uploading it onto this website for other people to see, now.

1st ) I would suggest for the first picture to be shown should be the 2nd picture because when people are exploring other texture packs, i was highly confused of what this pack since the first image is your profile picture.

2nd ) The red diamond idea is nice but it kinda looks of what the ruby ore looked like and i feel like i would get confused between the redstone ore and the red diamond ore (and for people who's colorblind. It doesn't really help)

3) It wasn't clear in the 2nd photo but are those bottom blocks wool? I think to showcase what blocks it is, instead of showing them all off in one image. I would do an image for each thing you've added like all the ores in one image, then the another set of blocks and such.

4. Also your pack.png needs to be 64x64


Other then that, it still looks good if you look it onto the surface