ex I don't have GD but I am 'sugar sensitive' (which means they've tested me twice for GD so far (am 20 weeks!) and they're doing it again at 28 weeks... feel like a bloody pincushion!).
Google around "the low GI diet" and see what appeals - do NOT cut out 'natural' fats (eg, butter, egg yolks) and don't bother about restricting calories. DO cut out sweets and (alas!) white flour-y things (I WANT A CROISSANT!)
I wake up extremely hungry and a bit woozy, and have found that something like cereal (insta-carb, v.bad for me) makes me feel great for half an hour and then dizzy and sick, something like two boiled/scrambled eggs, some sauteed spinach (often I make up a batch, sauteed with onions or mushrooms in stock and then keep it in the fridge to microwave) with a sausage or two sorts me right out and actually keeps me going till lunch. Ooh, or my latest favourite thing is an omlette with grated corgette in it, and a splash of soy sauce. Sounds weird, I know, but basically it's amazing! I'm replacing the 'toast' part of my breakfast with a base of something green, and it really seems to help.
I snack on beef jerky (mmn) and baby tomatoes/carrots, but something like babybels and other cut-up-veg or apples also works for me. Protein, protein, protein!
I DO still have the occasional sweet treat (DH's birthday yesterday, at cheesecake.. so good!) but I have it after a fairly high-protein, low-carb meal (EG last night's dinner was lamb chops and broccoli, and I didn't have any new potatoes, though DH did...) i've found that sweets or white flour or white potatoes or even fruit on an empty stomach sends my blood sugars rocketing and I don't feel my best. Tacking them on at the end of a meal, maybe once a week, is less detrimental (though still not ideal).
Obviously, you should talk to your MW or GP about it. I hope some of my main thoughts (Low carb mornings, protein, cook up nice veggies in advance so it's easy to microwave them. have lots of tasty meat/cheese on hand and snackable) are helpful until you do!