Design plays a big role in traffic generation.
so,give me some tips for best web designing.
I think you're a bit confused here. You need to generate traffic to visit your site - and only then will they see your design. It might influence what they do on your site, or how long they stay, but the design will not generate traffic.
Your question is much too broad and vague to answer here. There is a great deal of information in other threads in the Design forum which you will find helpful. There are also plenty of books about all aspects web design and there are online tutorials.
Try these resources, and if you then find you have a specific question, then please feel free to ask. Meanwhile, thread closed.