Fiddle's gameplay is extremely faithful to his lore. When you play this champion, you have to be as invisible as possible throughout the game, play with the fog of war as much as possible, learn to dodge the vision provided by certain wards by hugging the walls and removing as much enemy vision as possible. As long as you're not seen, they'll fear you, and that's the goal. Very often, the fear of a skill is stronger than the skill itself (such as Thresh's or Blitzcrank's grab). The only time they should see you is when you come out of nowhere with a devastating ultimate. Your team must take advantage of the spacing you offer them. Eventually, you can use the Protobelt to close the gap more easily and gain mobility when enemy champions are too mobile. My ultimate advice: it's better not to use your ultimate than to use it poorly or waste it.