Also is there a way to turn while attacking? I was trying to kill some of them deer types with sword that took about 20 minutes to swing. Am I meant to pick weapons to match my foes (slow attacks for slow movers etc), or does the attack speed increase as I upgrade it?
I'm new to MH so don't slate me for the noob questions.
1.- Monster materials are the ones you should keep mostly, but also other things like bones and such. Commodities obtained through the chief's son I believe are safe to sell/trade.
2.- Greatswords can turn while attacking, VERY slightly though. Planning your attacks beforehand is the best way to go.
3.- You've just earned a pearl of wisdom by yourself. Yes, use swift weapons for swift monsters. Weapon combos or attacks do not improve by improving the weapon. Actually they don't change at all. The improvement lies in stats only.
I don't think money will be a concern later in the game, so I just keep everything. If I want to make a lot of weapons ( instead of sticking to one type ) I will need a LOT of materials. And after awhile you will just be grinding the same stuff over and over getting money and materials.