What is the fastest way to travel from Shenzhen to Guangzhou

There are bullet (G) trains from Shenzhen north railway station to Guangzhou South, only taking less an hour. A good choice.

You could take the trains for SZ north as suggested in an earlier post or simply take the high speed rails from Shenzhen main station in Lohu to Guangzhou or Guangzhou East. These are far more frequent... every 10 minutes from 5am till close to midnight. The advantage is you needn't pre-book... simply buy when you want to go any day and at any time of year, even in peak periods. You usually don't need to wait long! The trip takes one hour and 15 minutes to GZE and about another 10 min to GZ station, depending on where you need to go in GZ. I recommend first class as it is a slightly bigger seat which reclines. Chris (I lived in SZ for three years).