I am on day 21 of my first ever juice fast (I'm going for 30 days). I've been reading this forum and any other information I can get my hands on regarding juice fasting for roughly three months prior to the start of my fast, but I am a novice faster... With that said, if you want to continue your juice fast, I'd say get right back on board. I think more than half of this is mental--at least my struggles have been. It's amazing how we eat out of such habit rather than because we are really stomach hungry. I don't think you have to wait days to begin fasting again. If you just ate salad tonight, I'd say start again tomorrow--just know though that starting tomorrow would (I think) be like starting on day one again. But hey, its better than blowing it completely. You'll see benefits in no time!
As far as an effective juice fast, I have been following Somer's advice: fruit juices in the am and veggies in the pm. I have 2 oranges, 1 apple, 1 pear, and 1 kiwi in the morning--yum yum. Another breakfast juice I really enjoy is two apples and two oranges. Its especially good if the produce has been refridgerated. I drink a veggie drink again in the late afternoon that consists usually of brocilli, spinich, cabbage, carrots, an apple, a cucumber, and sometimes a lemon. That is no so tastey. But I've actually grown to like it. I think its what your body gets used to. I have pinapple juice as a treat sometimes in the evening when I'm craving a snack. It really hits the spot. Regarding which fruits/vegs are the best for healthy cell regeneration, look on the www.freedom-you.com website. I purchased the "fasting to freedom" book but there is tons of info right out of the book posted on the website. There is an abundance of information about specific fruits and veggies. Also, I came across this website: http://www.whfoods.com/foodstoc.php?PHPSESSID=f8a2a11f1f5278b3601914c9dfb1a6ce
Its the "World's healthiest foods" and it doesn't talk about juice fasting but gives a ton of useful information about the nutrient content and value of fruits and veggies. I found it to be very informative.
Another favorite drink of mine that I have recently discovered (from "The Juice Lady's juicing Book") is actually a juice recipe for depression. I have found during my fast that there are days when I am really cranky and I thought I could tailor the juice to my specific health needs... The drink is 3 carrots, 1 pear, and 1 Celery stalk. I think it calls for kale also, but since I didn't have it in my kitchen, I left it out. The juice I made is really really good and it appears to work!
I hope I've helped a little--I've certainly rambled on and on...
Oh, p.s., don't forget to either drink a detox tea or do regular enemas!
Good luck with your fast! Start tomorrow, its a new day and your body deserves it!
Keep us posted!