Night time is the time I will over do it as well. Some of the things that seem to help it are:
1) Keep track of what you eat. After dinner, see where you are and how you fared for the day. Then if you have the candy bar, put it down and count the calories. It makes me think twice about eating something if I have to write it down.
2) I agree with others - keep your hands busy. Take up knitting, beading or writing. My grandmother used to shell pecans.
3) Exercise can be an appetite suppressant. Do yoga or stretching or take a walk and you will feel better and it will help.
4) Determine what is the trigger. Is it TV? Once you identify that you can work to stay away from it.
5) Like others have said, get some good alternative snacks. I like some of the chewy granola bars because they are sweet and only 90-100 calories and they are individually wrapped. Other ideas like yogurt or even a small bowl of reduced fat ice cream will work.
6) Drink herbal or chai tea in the evening with a little sugar.
I hope this is helpful.