Use the VS Seeker to your advantage and train wherever the Pokemon's trainers levels are the highest, before the E4 the best place is Island 1 (Approx 37 with some evolved Pokemon), since you cannot use the VS Seeker in Mountains.
Seven island at sevault canyon.
Keep fighting the Pokemon league or train in cerulian cave
The more you train your poke'mon, the more friendly they will become with you.
Seven island is a place where you can train your strongest Pokemon you can only access it by showing the sailor who took you to the SS Anne the rainbow pass.
There is no Wonder News in Pokemon FireRed, whatever that is.
Train at victory road
Explore, catch pokemon, train your pokemon.
At an efficent Pokemon on Pokemon Fire Red
If you train your pokemon or use cheats you can be the best trainer.
Train a larvitar to level 35.
train it to level 100!
Train it to level 23.
Seven island at sevault canyon.
Catch a pidey and train it to level 36.
A good place would be 7 island.
Keep fighting the Pokemon league or train in cerulian cave
Go to 7 Island, there are a whole lot of strong Pokemon there.