Try to keep nibbling throughout the day as it is often worse when you get hungry.
Things with strong flavours i.e. salt and vinegar chips often go down well.
Ginger can help - ginger beer (non-alcoholic), ginger biscuits or the ginger/vitamin B6 tablets from Blackmore's/Elevit
Brushing your teeth can be hard - you could try some different flavoured toothpaste (not mint)
Cooking dinner or even the smell of cooking meat can bring on nausea - get someone else to cook, eat out, try vegetarian.
If plain water is hard to take try herbal teas, weak juice watermelon, icy poles, yoghurt, gatorade or jelly
There are some medications which can help and are known to be safe in pregnancy. You will need a script for these. Mylanta or gaviscon is safe if you have indigestion.
Don't get too stressed about eating healthily. If you are feeling sick just eat what you can. The main thing is to keep hydrated. Losing a little weight in the first 12 weeks is not uncommon. You will almost always begin to improved by 12 weeks and then you can get back to eating a healthy, low GI diet.