So you want to pack a texturepack? Well you've found the right place! To pack a texturepack follow these simple steps!
(This is how i do it)
1. Go find a texturepack in your texture pack folder and copy it to somewhere like the desktop
2. After copying it go inside the zip and delete everything in the folders (Ex Mobs. Delete everything in mobs folder but not the actual folder)
3. You should have a zip folder with a couple of folders. What you do now is open up your minecraft.jar
4. When you've done that scroll up or down until you find the folders.
5. On the list you should see a folder called Mobs and so on and so on. What you have to do is paste everything like the images from mobs all the way into the mobs folder in your texturepack.
6. After you've done that Start painting! :D
7. When you've finished save it.
8. Publish! :D hope it helped