It depends on the database itself. In software development particularly web application, you can't have optimised database straight away. Off course, the normal practices should be applied and the database should be optimised as it has to, but what I have learnt, some of the attributes of various tables are differently manipulated to that when it was designed. It is always a good idea to revisit most of the database as there is always a scope for improvement. 

Coming back to your question, more detail is required to get a precise response.

thanking u for u r response sir you are mention more details so i required that details.

can u mention what they are

i can go with index for db optimization can u mention what are they 

Views, indexes and stored procedures.

Indexing.