Flying - This is the fastest way to Yangshuo. From Hong Kong you can fly to Guilin in about 1 hour 30 minutes then take a taxi or a bus to Yangshuo. A taxi takes about 1 hour and costs about 200-250RMB. The bus takes about 1 and a half hours and costs about 15RMB. There are two bus stations in Guilin. The formal one is called 'The Long Distance Bus Station of Guilin', the last bus to Yangshuo leaves at 8pm. The informal one is just outside of South Train Station of Guilin. This one operates a much more flexible time schedule; it usually leaves when the bus is full. Be aware that the driver may hassle foreign travellers to pay for their luggage.
Bus - You can take the K.C.R (underground train) from Tsim sha tsui to Lo Wu. After passing through customs walk outside to the square and on the left is the bus station. You will probably find someone who speaks English there who can help you buy a bus ticket straight to Yangshuo. The bus takes about 10 hours and most of them run at night. You can buy a ticket for a seat or for a little more money, a small bed. Prices vary from 160RMB up to about 500RMB depending upon the time of year. At very busy times like Chinese New or Golden Week tickets may be limited.
Train - The train from Lo Wo in Shenzhen takes about 12 hours but is more comfortable and safer that travelling by bus. Follow the same instruction as for the bus but turn left instead of right in the square and you will find the train station. You need to get a train to Guilin as there are no trains straight to Yangshuo at present. On arrival in Guilin take a bus from outside the train station to Yangshuo, see above for detailed instructions. Note; you will need to know a little bit of Chinese to be able to buy the train tickets.