For a while there I regretted extending Aard's range. But then I started fighting flying enemies, and, boy, was that a good decision!
Two birds with one stone.
Just refer to the crafting/alchemy menus when you need to - no need to memorise.
For the ingredients:
- Herbs come from the environment or herbalists (located in some villages and most large towns).
- Monster parts are named after the monster they belong to and will randomly drop from said monsters.
- Crafting supplies like metals or leathers can be bought from blacksmith/armourers or acquired by disassembling weapons or armour.
- Silver is rather rare and can be acquired by disassembling silver swords.
- Disassembling items is a good way to get the other items not listed here. Be careful doing this, because it will only break down a crafting ingredient into a lesser form.
- Strong alcohols (for making potions) seem to be pretty much any alcohol you can buy... I don't personally understand this aspect myself. You'll find more than you need by looting points of interest.
For crafting/alchemy diagrams:
- Find them at treasure sites or points of interest, generally as the big chest contained within, or even off the beaten path somewhere. Far as I'm aware, they're randomly generated so there's no specific place to find any one diagram.
- Witcher gear is the exception to the above. The diagrams are at set points in the world. Also, if you have green (witcher) gear, don't sell it because you can upgrade it down the road.
For dealing with encumberance, the main things hogging up your inventory will be animal pelts or excess equipment. Just sell or disassemble them while keeping my above tips in mind. And one other thing, junk-classified items will say whether they have a crafting purpose or can be freely sold.
Hope this help.