So in For Fame and Fortune, the more you use a weapon the more it improves.
For example, if you stick with a sword for more than two levels, it's attack will increase by 1. If you stick with the same sword for two more levels, it's attack will increase by 2.
You can also find an enchanter deep within the ruins that will upgrade your weapons in return for a quest item.
Enchanter quest items can be found on the same map, but will probably be guarded by a trap or a tough enemy. Some Enchanters may be willing to give you an enchantment for free, if you have a certain item like Enchantment Book.
That's pretty much it for improving and upgrading weapons.
Just going to toss this in here, but a demo is in the works and is almost ready (will be released Friday). So keep an eye out for that.