Grade B pencils, sand paper and cotton - specifically for quick shade shadowing. you can learn the technique over here .
here are a couple of youtube videos
Balancing is not necessary, yes you can place sphere on a pyramid or vice-versa.
For more info Visit natasketches.com
You have to enroll for the short term sketch development course then only you will get the access for the assignments blog.
If you have enrolled in DQ Labs, you will get access to the DQ edge material but you have to ask for manual access for the same.
For admissions in the B.Arch, students are required to have passed the Higher Secondary Examination with subjects of study prescribed by the Council of Architecture. Minimum 50% marks (45% aggregate for Reserved category) in 10+2 Examination or equivalent with Mathematics as subjects is required for admissions. NATA is conducted by the Council of Architecture. Higher score in NATA increases chances of admission in known University or institutes, however, minimum 40% marks in NATA is expected by most Universities or Institutes.
Previous years questions are available on DQ Edge itself, arranged subject wise. You can go to "take a test" tab for reference of which & what type of questions are asked.