First pregnancy I was only sick a handful of times, but this time I'm now 30 weeks and still being sick every day. It's only 1-2 times a day now, compared with the 10+ times a day I had for months on end. Both boys 
I found I could keep down ice-cold water, so always keep a jug or 2 in the fridge. Cold Sprite/7-up worked too. Contrary to the rest of the world, eating made me feel much worse in the first trimester, but then at about 13 weeks I suddenly switched to eating made me feel better.
Digestive biscuits were great, and so were twiglets. I guess they're sweet or savoury extremes?
Worst thing to eat was chilli con carne with rice. When you puke it up again it just sort of sand-blasts your throat with the rice & minced beef, then the spice burns your raw throat.
Lots of ice lollies and ice cream was good too! Ice cream's nice and cold, isn't too heavy on the stomach and I think the dairy helps with the stomach acid. It's also not too bad at all if it comes back up.
Have just realised I now appear to be choosing my meals/food based on how unpleasant it'll be to throw up. When will this end?!