First, I am not the best advice on this, I haven't harvested once yet (coming up in few days!). Then... It's the calyx you wanna smoke. (search Google image for calyx marijuana) but the trim you can always use to make hash, or other things. I plan on making cannacap, but that's more a "medicinal" use rather than recreative.
There is the fan leaf. That's the leaf material that was created during veg, the big leafs. Remove those obviously, you could throw them because they have the least amount of trichomes (it falls from the calyx unto the leaves). Then there's the sugar leaves, it looks like fan leaves but much smaller, and poking out of the bud. You can remove those by cutting what's coming out of the bud, or if you have good scissors you could try to reach in the bud and cut the maximum of those leaves off. You can save those sugar leaves (it's called sugar because it has lots of fallen trichomes on it, it looks frosty... Or at least I think it called that because of this.) to make side stuff. But the best smoke, the best high, will come from the calyx, full of trichomes etc. Does that help?