Mains

For people who have written mains before -

How many questions have you seen directly from test series ? For other questions (most of the qs) , which are answerable but need correlation, do you spend a few seconds to a minute planning your answer or are able to write it immediately? What helps in strengthening this ability - is it a mix of revision or answer writing, or answer writing over revision once you are done with content?

Please mention paper-specific suggestions, if applicable. Thank you!