If you are interested in B.Arch then you can appear for JEE Main paper II and NATA.

Before starting your preparation make sure you are aware of the complete syllabus and exam pattern.

You can make your time-table. So, that you can complete your syallbus on time and you get proper time for revision. You can also set your targets.

In order to prepare for these exams make sure your concepts are clear.

Refer your text books for class 11th and 12th to prepare for mathematics. 

Work on your observation skills and drawing to prepare for the Aptitude and Drawing tests.

You can also make your important notes and flashcards it will help you at the time of revision.

You can also solve as many as mock test series for your practice

-A Complete Self Study Guide for B.Arch  Entrance Examination (English) by P.K Mishra, Arihant Publications

-Verbal & Non Verbal Reasoning Book by R.S. Aggarwal,

-Architecture Entrance Book by P.K. Mishra

Good Luck!!