How does Amazon decide in which order to list products on its search page?

[amm]

When you search for an item on Amazon, how is it decided which items come first? If you're listing an item, how can you get it to appear near the top of the search?

I listed an item on amazon and it only appears in the search if I search for the item's exact name. It doesn't appear even if I search using parts of the items name, or the type of item, even though these are both keywords that I used when creating the item.