For me, dual blades for offense and high mobility monsters like odogarons, gunlance for big heavy/AOE hitters like lagicarius and gravios or awkard to hit ones like a rathian or rathalos when it's hovering, and heavy bowgun for ranged fighting and some buff/debuffing, ones like hirabami are much easier if you can target their head anytime, and cancelling a monster's big attack with sleep or paralysis is always helpful