Monster Hunter: World - 12 Incredibly Helpful Secrets You Need To Know
5. Use The Ecological Researcher To Find Weak Spots, And Which Creatures Drop What
Remember a few points back, I mentioned the Ecological Researcher? Don't skimp on this guy, as he's the key to knowing precisely where on a beast you should be attacking, and with what.
Pages like the above are unlocked by repeatedly tracking multiple pieces of evidence pointing you towards a given foe, and then taking them out. Think of it as accruing a currency of pure data beforehand, before "banking it" with the researcher.
The game will actually prompt you to do this when you return from a hunt, and you can see how far along you are per creature by how many tabs have opened up along the top of the screen. Use these screens to specify something like blunt damage towards an Anjanath's head, or if you're farming the forever-elusive Monster Bone M, you can find it on Barroths, among a handful of others.
A good offence is often a good defence, but an even better one is knowing precisely where you're going to strike.