Its not by trial and error, but it will be by some guesswork.
If you map it out, you can see the various components that string together to make an object. There are other, very similar components available. What if, instead of using a maple plank to make that bow, you substitute a willow plank. will you get a willow bow? if you can make bronze chainmail, from bronze nuggets, a bronze ingot and some bronze rings, can you do the same with brass? What about iron?
If you can make a tabard by hooking up a tunic and a pair of sleeves, what if you use a leather tunic and leather sleeves? Can you add gloves to it?
The organised ones are going to crush the dabblers, at least until a database is built for the ones who aren't interested in figuring it out.