How can i go to Dongguan from Guangzhou?

Both train and bus are available.
By train: At Guangzhou Railway Station or East Railway Station, there are many intercity bullet trains. You can arrive in half an hour.

By bus: Many buses are ons schedule in Guangzhou Bus Station and the Privincial Bus Station. Both statins are within walking distance to Guangzhou Railway Station. It takes an hour to DG city.