For me its picking the better option for me
If its an obligatory 3 course type thing where everyone else is having a starter and you would feel awkward - take the soup or the salad starter
Choose a main wisely, steak or fish as plain as possible - ask for sauce on the side , ask for a veg or salad side or plain boiled potatoes
Go for a dessert without pastry
When eating out as part of work, its not a treat, you are just refuelling
Buffets and parties, fill the plate with salads and pickles and take proteins which arent covered in pastry - leave the sausage rolls behind. Eat the quiche fillings, leave the pastry. Pick stuff thats not bite sized that pops too easily and mindlessly into the mouth. Take a rice dish over the pasta smothered in mayo Take just one dessert
I find that as long as I have more veg/salad/fruit on my plate then beige carbs I can get happily full, not feel Im missing out and keep on track . If I go for the beige carbs - all bets are off and I over eat. But thats me, I know bread, pastry and biscuits/cakes bypass my off switch. I can stop at 4 wee sausages, add pastry ie mini sausage rolls and a dozen will be down my neck
Wine is very calorific so if you are having a drink, switch to a Gin and slimline - more slim then gin and have just slimline every other drink - no one will notice