Hi,
We have read following books for Verilog:
1)Verilog HDL by Samir Palnitkar
2) Advanced programmable Language by Dr.Cielleti
First book that i have told you starts from very basic level & second one is good if you know some basics about Verilog & it also includes simulation & synthesis as well.
If you study these books,not all book but important chapters ,I can assure you that you can be good at Verilog.
If you are targeting Xilinx FPGAs, also read chapters "Verilog Language Support" and "HDL Coding Techniques" in the Xilinx ISE "XST User Guide".
Looking back at when I learned Verilog, I wish I had started with those Xilinx chapters instead of reading Verilog text books. Most folks recommend Palnitkar's book, but I think it is off-track for modern FPGA design.
I can't find that Cielleti book. Please give a link.