Hi Jitentra,
SAP has removed the exam C_TAW12_71, so you can only apply for latest SAP ABAP certification exam C_TAW12_731. However, You can find difference between these two certification exam at given links.
Apart from this, you can refer the given site where a lady from Japan has shared her success story and tips with complete guide for scoring high in SAP ABAP certification exam.
How I scored 88% in My SAP ABAP Certification Exam | SAP ABAP Certification Guide
Hope, it helps you a lot.