Hi Cosy,
my 2 penneth worth..
I would start by knocking on the head those carbs that it's difficult to portion control. So that's pasta dishes where the pasta is the meal. I found that basically rules out pasta. If you're going to have rice, then Basmatic is probably best and do as Grazer says, make a note of how much you have and then test after 2 hrs. I find I can't tolerate rice at all, but some can.
Bread for me is a real problem - but I switched to Burgen bread initially (its in all the big supermarkets) and this helps cope with the need for bread.
Other things, like cereals - well measure the portion and then test. After a while you start to guard the carbs you can have and wont want to waste them on small snacks. I would far rather have a whole bowl of porridge now then a small piece of bread.
I kept a daily food diary for the first couple of months. It's good to be really intense about it (though you bore everyone silly). Write down what you have, test, try something else, write it down, test.. if you can, bung it all in a spreadsheet and draw a graph - it's really motivating to see the numbers fall and it inspires you to go further.
It can be daunting in the supermarket when there are now whole aisles that I don't use - but it is possible to eat this way and the effect on your health can be miraculous.