Help... Need opinions about detox

Long story short, I'm not a healthy eater nor a 3 meal a day type of person. I want to try the three day juice detox to help me out. Need to loose 15lbs by Oct. I've never juiced before so I'm wondering if anyone has advice on if I need to do anything special the day before...?...

Before telling me about exercise and not eating sweets, etc I want to say... I don't eat sweets and no I'm not just saying that. I don't like candy cake cookies or anything with high sugar, I rarely drink soda, tea, or anything other then water. And I exercise almost daily. Sometimes twice a day. I got that part it eating three square meals a day, and eating healthy food on the go.

Thanks for the help!