• It gets easier. I had a several some false starts. For me, once I got over the first ten to fourteen days, I was on a roll. My advice is to be strict in the first two weeks, and if you try and fail, just start again.
  
  
• Exercise every day. I don't do vigorous exercise, but I've made a point of going for my "daily constitutional" walk, even if it's just a matter of taking the stairs when I'm going somewhere anyway. Apparently there are muscle-toning exercises you can do even if you're on strict bedrest, but you'd need to ask a professional about those.
  
  
• Water is your friend. Caffeine, juices, softdrinks, alcohol and milkshakes are not. Plain water is fine, but the sparkling variety is mildly ant-acid, and I find it helps with nausea and heartburn so is good with meals in pregnancy.
  
  
• Mornings are especially trying, because you'll be starving and tempted to go for a quick-fix of carbs, and that'll stuff you up for the whole day. Ditto the midnight snack. Homemade smoothies can work well here - whip up something just before bedtime based on plain natural/greek yoghurt, fruit, milk or cream and perhaps a few nuts, and it'll be there and ready to get you out of bed first thing in the morning. I follow this up with a cooked breakfast - a bit of rindless bacon, eggs, or some sausages. If that's too much for an early start, pre-prepare some hardboiled eggs - you can even take a couple with you on the road.
  
  
• When you make a meal, make a snack, too. Make dinners with a little left over so you can wrap it in wholemeal flatbread plus or minus some added lettuce or cheese for your mid-morning snack the next day.
  
  
• Use different herbs and spices. It will add variety and stop you getting bored. It can also help overcome some pregnancy-related food aversions.
  
  
• Have a weekly "cook-up". Make big batches of things you can store, like soups or casseroles. Store them in snack-sized portions, and use one for a snack or two - plus or minus some wholegrain bread or salad - for a meal.
  
  
• When you eat out, check the starters menu. Main meals are often carb-heavy, and the restaurant carb of choice is usually high GI - potatoes, white rice or white bread. Starters, by contrast, often focus on proteins or vegetables (except for the ones which are exclusively carbs - obviously don't order those). It can sometimes be better to order two or three starters instead of a main - a little more expensive, but then you're drinking plain water instead of wine, so it evens out. You might also be able to ask the waiter about "upsizing" a starter to main course size. In any case, make sure s/he brings your starter at the same time as everyone's mains, because otherwise they'll have to sit and watch you slowly digest your whole meal and no-one will bring their food until it's all cleared away.
  
  
• Keep a snack box ready and waiting to be popped into your handbag. Nuts, cheese, wholegrain crackers, apricots... take it with you wherever you go. Good for emergency hunger pangs or nausea, and it'll keep you reaching for the first (high GI) snack you see when you're out - or even at home!
  
  
• Swap your carbs. Go for higher-fibre alternatives. Jasmine rice and long grain rice are high GI, but you can swap them for basmati or brown rice to keep things a bit more in check. (A good general rule with rice is to steer away from the fastest-cooking ones and towards the slowest-cooking ones.) You can also ditch potato in favour of sweet potato or yams, white/refined breads and pastas for the more sustaining wholegrains/wholemeal varieties, and flaked cereals in favour of noodle-shaped bran cereals or oats. You can also swap flavoured yoghurts for unsweetened, natural yoghurts. Make sure you balance the meal with a nice serve of protein.
  
  
• Don't overcook it. You want your body to spend time digesting the food, not your stovetop. Examples: do your pasta al dente, and your vegies on the crisp side.
  

Add your own tips in the comments!