If you want to know how to level up my pokemon fast in emerald here are some ways:
- have a strong pokemon, attach exp share on the pokemon you want to level up and beat the E4
- battle with lucky egg (unsure as to where to find this)
- rare candy
- daycare (will delete moves for new moves)
- match call
- beat wild pokemon
- If they're low level fight the Whismurs in Granite Cave.
- If they're 20-ish battle the pokemon on Routes 110 and 117.
- sky pillar
- victory road
please post any other hints