Practising isn't everything, though it's the most long term. I would recommend Observation and quick doodles limited to 30 seconds or maybe a minute. If you're in a situation that you cannot draw it, note it down and take the opportunity to practise it in your own time. Practising blindly is shooting in the dark.

Practice in different views, and importantly the previous year papers.

Yes ,class 11th and 12th mathematics is asked.

Speak to any of the faculty regarding the same and request a meeting.

This happened for me too. I dont know why it happened. I have completed english but it completed in the coverage chart as only 94 percent complete even though all of it is complete.

there isn't a separate section for riddles but there are a couple riddle questions asked in the practice set 1 (MA) in the take tests tab.

Yes, CEPT Ahmedabad is one of the top ranking design colleges in India.