Do not use the pheromone power-ups until you have a setup that can handle bigger fish. Save pheromone power-ups until you are ready enough to handle the increased tension from huge fish. When purchasing upgrades, choose those that are permanent instead of the consumable power-ups. Improving your rods and lures will be more useful in the long run. This will let you lure larger and rarer fish, as some of them will require top tier equipment to be caught.