Upon crafting a bronze ingot, the player gets the achievement "Bronze Award".
Bronze ingots can be crafted on the standard crafting table. Place a copper ingot and a tin ingot into the crafting area or a standard crafting table in any arrangement to create one bronze ingot (before Public Beta 25 update two).
However, a more efficient way to make bronze is to smelt it in any alloy forge by putting the tin ore or ingot into the alloy slot above the copper ore or ingot, or vice versa. This is more efficient than crafting, as it creates two bronze ingots for every copper/tin pair instead of one - thereby outputting the same number of ingots that went into the process, instead of half as many - and also uses less coal.
As mentioned above, bronze is most notably used in the crafting of bronze equipment and armour. Bronze items are crafted on the standard crafting table. The durability of bronze equipment is slightly worse than that of iron - however, bronze tools are very useful, since they have the same mining abilities as iron tools and are not otherwise significantly worse. Therefore, crafting bronze tools instead of iron is a wise choice that can save a significant amount of iron in the long run, as most faction armour and equipment requires iron to create.
Other important uses for bronze are crafting the Horn of Command and the Sword of Command. They can also be used to make bronze chandeliers, and as with other ingots they can be made into a mineral block for more compact storage or decoration. While in this form, bronze blocks can be used as a beacon base.
The most efficient use of bronze is probably in making crossbow bolts- they can be made with either iron or bronze- because bronze would produce the same crossbow bolt as iron would.