I reguarly get questions from students who are looking for a position as PhD student. Here are some hints for those applicants:
1- The positions as PhD stundents are very limited compared to the number of MSc students. So, if you apply and get a negative answer, you are not alone. Do not give up!
2- The financing is usually a major crerion. If you have financing from e.g. your home country, a ministry, a company etc., it would be easier to find a position. However, if you apply for the positions with salary or scholarship, you have to compete with the other students, which make it much more difficult.
3- Try to contact the professors whom you are interesting to work with. You should avoid general e-mails, since nobody answer.
4- Try to make personal contacts with those professors in e.g. conferences, workshops etc., even if you have to go abroad for such conferences and pay for it.
5- One major merit in selecting the students is to have publications (in scientific journals). You should work hard to do some good work in e.g. your MSc thesis and try to publish it. It increases the chances to find a position.
6- Many MScs try to study another MSc again, in order to get in touch with some peoples and increase their changes. It sometimes works!
7- The grades in your MSc and even BSc are important.
8- The social parts and teamwork are also important to get a position. Do not understimate it!
9- Try to get a good references. The reference letters that are handed over to the applicants are usually useless, since all of the are positive and not real!
Think about these facts and good luck in finding a position!