This is something I have experimented with quite a bit! Here is what works for me to get into Ketosis in less than 24 hours:
1st start your 0 carb day. Make it a true 0 day, meaning 0 carbs. Don't even have eggs due to there .25g of sugar/egg. I would also advise skipping the fiber/veggies for a day. Keep your diet high in fat through out the day since before you started this you probably consumed carbs I like to keep meals 1-2 lean protein with, clean fats. some thing like 4oz Salmon& 2.5 Tbsp olive oil will do the trick. Meals 2-8 (yes 8) should contain higher fat. Keep most of the fat clean until meals 7-8. so Olive oil, flax, Coconut Oil, & EFAs. Keep protein very low. I like to go about .5g/lb of body weight (don't worry about losing muscle in a single day, in order for this to work you need a large deficit right off the bat)
The rest of my meals are very high in fat keep fat cals about 65-70% of your daily intake. Try to get in about 1g/fat/lb of body weight, and .5g/protein/lb, 0g carbs. After meal 6 or 7 Its time for a long duration low intensity cardio session. 90 minutes on the elliptical will do the trick. My last 2 meals are very high in fat I will have some thing like 6-8 pepperonis with sharp cheddar or mozzarella cheese on them.
For a 200lb person this breaks down to about 1800 fat cals, and 400 protein cals leaving you at 2200. This should be a nice deficit in combination with the 90 min cardio session. Avoid sweeteners, citrus acid, aspartame, soda, ect... This may not effect you but It may effect others. I have tested this and I was in deep Ketosis less then 24 hours later, while properly hydrated. I confirmed with multiple checks. If you don't make it into ketosis try the same protocol with Fasted AM cardio to start @ 60mins, and 60mins at night. You can also decrease protein cals and fat cals slightly.