I train almost all of my Pokemon at Route 3. If you run around, not in, the tall grass, the grass will start to shake. There is a big chance that this will be Audino. Have your chimchar hold a lucky egg. Fight Audino and immediately switch to a strong Pokemon. (You could also use a repel to find shaking grass.) This is tried and tested by me and my very high leveled Pokemon.
If you want it to be EV trained go to Advanced above and click EVs, go to EV training locations.