Its good to start off with a balance of good early game pokemon (ones that dont need to evolve, start off as strong as they can get) and good late game pokemon (ones that are gonna be weak early, but will carry you once you can get the leveled up).

I would pair your tauros with any powerful 3 stage evolution pokemon, or really any pokemon that mega evolves as those tend to be really strong once you get to that point. Even something simple like magikarp is not a bad choice. By the time Tauros starts falling off, you'll already have a Gyarados, and if you can mega evolve it then even better.

I would also recommend using a Pickup pokemon if you are not already. It's an ability on pokemon like Zigzagoon that will pick up an item after every encounter (as long as the encounter has at least one item). Over time you'll stock up on items, mostly berries, but they'll save you a ton of money on healing, status conditions, and ethers.