Point-Counter Point on Catholic prayers to the Saints
It is worth reading first to see what their thinking and arguments are so we can understand and be able to address what they believe and not just what we think they believe.
Here is a tract by Catholic Answers on praying to the saints from a Roman Catholic viewpoint:
Here is a Protestant counter point article answering the above. You might want to think what your answers would be first before reading this to test your own reason and knowledge of the subject.