Aargh I remember it well! Just waiting for it to start again very soon (nearly 5 weeks now...)
I found orange juice out of the fridge really helped. I definitely found that it was in some way connected to my blood sugar. When that dipped, the nausea grew legs. So anything that raised my blood sugar fast would help - some people really rate lemonade and coke.
Also, really really cold water full of ice, with a slice of lemon in helped. Lemon is supposed to help nausea, it just smells so clean. And crunching ice cubes was nice.
Ice lollies - literally the ones that are just cheap fruit flavoured, no dairy.
Crisps (ready salted, mini cheddars)
Bacon sandwiches, but I couldn't stomach the crusts 
Chip shop chips
As soon as I felt the nausea building I would have some juice whilst making food. Eating really helped, but I had to eat soon enough before I felt too sick to.
I couldn't eat vegetables for weeks, and I love them.
It peaked for me at 9-10 weeks and then gradually tapered off and I felt better by about 13/14 weeks.
Utterly miserable though.
If it's too severe for you to keep enough liquid down/you lose a lot of weight fast you need to seek treatment from your GP. Check out the hyperemesis support thread on here if you need advice.