writing process is a snowflake

I have a number of critique partners now and I've had scads more if you add up those from the past. And if there's one thing I've learned from all these writers it is: everyone's writing process is a snowflake--unique. (Please don't confuse this with The Snowflake Method of writing.)

I'm a pantster; I do not plot my novels in advance. Does this mean I have to do revisions? Definitely. Would it be more efficient to plot the book out in advance? No. The Muse is a tricky mistress. I tried this once and it sucked all the joy out of writing for me; I never finished that novel.
On the other hand, I have a writer friend who totally plots the book out in advance. She creates a detailed ~50 page outline before she starts the book. More power to her. Thus, obviously, any amount of plotting can work.

I do usually start with a Big Idea for my novels. Alternately, I have a writer friend who couldn't tell you what the Big Ideas are for her novels even after they've been published. Any amount of Big Idea can work.

What works for a lot of writers is to give themselves permission to write a crappy first draft. Then, you can go back and fix whatever you personally need to fix in rewrites. One of my critique partners has trouble with dialogue tags. One of my critique partners has trouble with descriptions. One of my critique partners has trouble with adverbs. IMHO, if you stop and obsess about getting everything perfect right out of the gate, you'll never make it to the finish line, aka "The End."
But, if you need to obsess, go for it. :)

Take advantage of your snowflake. Do whatever works for you! Good luck!