This is also something that I am trying to be conscious about. I have started taking smaller plates, filling half with salad and or green vegetables, the remaining half is 3/4 full with fats and proteins and the last portion is carbs. I eat following the glucose goddess approach too: veg first, proteins and fats second, carbs third. I found that this means by the time I get to the carbs, I often won't finish what's on my plate. Her book is brilliant btw. I really enjoyed it and it was an easy read.
Being mindful seems to help, I noticed recently that I was piling my plate a lot higher than I was 2 months ago, so I need to tone that down. I also never go for seconds anymore.
And as other said... lots of water. I find it better to drink iced water, I don't know why but it works for me.
I am also avoiding sugary snacks at the moment, I have a habit of reaching for chocolate biscuits around 2pm, so I bought some proteins chocolate mousse things from Lidl. It's an aversion tactic at the moment, but I am trying to wean myself off this sugar hit altogether. I do have a kiwi a day though. And I have pickled onions and gherkins around for it I really really really (think that I) need a snack.
I also no longer snack in front of the tv in a night. This is a hard habit to break, and as someone else said, I have been going to bed early instead. So I wake up with loads of energy... win win!
It's really hard, to break these habits. And it doesn't happen overnight. But stick with it, taking each day as it comes. You know that you are getting enough food, even if your body is telling you it wants more.