Hi bethany
If you have been on DAFNE there is a lot of portion weighing and counting there, and you are given a book with the average weights and carbs in. If not you can buy a similar book from any book shop listing carbs, since so many count them for Atkins etc. I guess it is all about practice, at first you need to weigh things a lot, maybe make your own rice so you can weigh it and get used to the portion size you need. Then when you get takeaways, don't eat them out of the box, measure the portion onto a plate (smaller plates trick you into thinking you have more food, if you think the portion is small) and put the rest away in the fridge for the next day. Takeaways are usually in very large portions, far more than you need. Indian is especially bad since it is full of sugar and cream, so even if you restrict the rice, naan and poppadoms you still eat a lot, and then there are the lassi drinks and desserts. Pizzas are pretty bad but since they come in slices it is easier to measure. Then as aymes says, keep checking your BG regularly so you get used to the effects of different sorts of foods and how much and when you should have your insulin.
Although takeaways are nice, my biggest piece of advice is not to have them very often. It really is not much effort to make some rice, you can buy readymade sauces if you don't want to make them, and you can add exactly what you want. Or if you like pizza you can buy bases and add your own toppings. Or it is a little tricky to make your own chips if you arent used to it, but they taste much nicer if made from real potatoes and cooked in the oven rather than deep fried. Plus for all these things you can weigh and count exactly what is in it and use proper fresh ingredients.