My dog is 8 months old and just recently started vomiting, most of it was food but now its just liquid. What can I do to help her feel better?

Take her to the vet.

Sorry but we can't diagnose on this site and your pups could have anything from Parvo Virus to Poisoning to an upset stomach.

I second the motion of a vet.
Is your dog defecating? Eating? Drinking? How is it's attitude?

You owe it to your dog to give it the proper care, which means taking it for regular vet care.

Take her to the vet. She could have gotten into anything, or she could have a virus like the experts suggested. It could be one of several things, and without a proper examination you just can't be sure.

It's already been said, there is such a wide spectrum of things that could be wrong. Take her to the vet.
But in the mean time, you need to make sure she stays hydrated. Pedialyte is one of the best of you can get her to drink it. You may need to put some flavour in the water. Make sure she doesn't drink large amounts at once, this will only make her more sick, and loose more water. Let her have a few drinks, take away wait 5 minutes, and give some more.

If this were your child, what would you do?

Take her to the vet, she can become dehydrated very quickly. Dogs that throw up all the time and stop eating could mean something bad could be happening... possbly a blockage

This makes seven responses you've gotten. I'll make it unanimous, get her to the vet. Seldom do all six of us agree, so that should tell you something.