I walked towards Saffron City and leveled up my team by battling, then I healed at the Pokemon Center in Saffron City once I arrived. I wandered around a bit and then I headed for the Saffron City Gym to challenge Sabrina. I got inside and I warped around to the different rooms within the Gym. I battled the Gym trainers and I left to heal after I beat some of them. I eventually returned to defeat the rest. I found Sabrina's location within the Gym, but I had to leave to do some last minute training. I headed for the route between Saffron City and Lavender Town and I trained there for a little while against the trainers. I returned to Saffron eventually, healed and returned to the Gym to fight Sabrina. I saved there.