You must eat normally and not starve yourself, or you will force yourself to do the same every week. My weigh in is at 7pm, I eat breakfast/lunch/snacks normally throughout the day, but wait til after weigh in to eat my evening meal.
As its your first evening weigh in dont be too disheartened if it shows a gain, or a loss less than you would hope - changing times will definitely make a difference, but it wont be an indication of your overall weight loss. Once you get into the routine of evening weigh ins the comparison will be consistent and more representative.
The main thing to remember is consistancy, whatever you do before weigh in, keep it the same every week, and make sure that its sustainable (ie not starving yourself all day every Tuesday!)