Purchase souvenirs from your stay in Guangzhou. There are numerous street markets located all throughout the city, including areas near the station. They are loosely organized by theme, so antiques will all be one street and clothes may all be on the next street. Explore alleys to get the best bargains.
Enjoy the dining in the area. The flavors of this section of China are different from those in your destination, so enjoy the nuances of local foods while you're there.
Visit a ticket office (found in the train station), your hotel's front desk, or a travel agent a few days before you travel in order to book your tickets. Ask at that time where to pick up the tickets that you book.
Pack your travel documents securely. Pick up your ticket a day in advance and pack it safely along with these other documents.
Pack your belongings. Be sure to take those things which you will need for this long train trip, including activities (such as a book to read or knitting to do) and snacks.
Arrive early at the Guangzhou train station. Trains generally arrive and depart on time and your early arrival facilitates this process.
Board the train. Expect the train authorities to look over your documents carefully.
Find your seat or sleeper and make yourself as comfortable as possible.
Keep your camera handy. The ride between Guangzhou is beautiful and will give you many opportunities for taking pictures through the windows.