Question

Is there a way to make a Pick-up ability work faster and to make it get better items?

Answer 1

Its random so you cant make it faster. To get better items you need to level you Pokemon up to high levels. Use this.

Answer 2

To make it work faster you could put multiple Pokemon with pickup in your party and to make it get better items you have to raise your Pokemons level. This is the item list for pickup: http://bulbapedia.bulbagarden.net/wiki/Pickup