There is no easy way to database design. Database design is more an art than science. Every database is customized to suit a particular application. It calls for hard work, meticulous, and patient. The basis of database design depends on the result and quality of requirements gathering and analysis. A well designed database will capture the workflow and business rules of an orgainization.
You will have to make many decisions in the designing process. Guidelines and principles are available in making such decisions, but they are usually about "what not to do" instead of "what to do". So, ultimately you are left pretty much alone to make the decisions.
Refer:
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10+pitfalls+of+database+design[
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2.
Fundamentals of Relational Database Design[
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