I jumped in with both feet as soon as I started. I think it's easier to change everything in my diet all at once instead of introducing changes gradually. It takes approximately 60 days to form a habit. I'm halfway there, with 30 days left to go.. I am forming the habit of low carb eating until it becomes second nature to me.
Giving up carbs is a lot like Gidget said--like quitting smoking. Many people find it easier to go cold turkey and get the withdrawl over and done with, rather than dragging it out for months with nicotine patches. Dump the carbs immediately, get over the three day withdrawl, and get on with a new, healthy lifestyle.