Liquid diets do help sometimes, though usually it's better to be supervised by a doctor if you're sticking to liquids for more than a few days. Doctors can prescribe supplements like Ensure or Fortisip, which provide all the nutrients and energy your body needs in liquid form. They can provide everything you need, with no need for any food, or they can be used in combination with normal foods. You can also buy similar supplements without a doctor's prescription.
If you're expecting to stick to liquids just for a few days, just go for the things you know suit you best: milk is a good one for me, and provides calories, but for some people dairy is a bad idea. Smooth soups are generally a safe bet, but won't provide many calories, so you'd need something more substantial if you don't have many fat reserves to draw on for energy - maybe Lucozade? If you drink fruit juice it may be easier on your stomach to go for less acidic ones, e.g. apple or mango juice, not orange or grapefruit.
How do you do with semi-liquids like yoghurt, ice cream, custard, jelly? If you can manage things like that you'll have a lot more options. When you introduce solids again, start with semi-liquids and very soft foods; there are lots of these if you want more examples.
These last two may sound wrong, but Coke drunk at room temperature can settle your stomach. And hot chocolate always seems to go down well with me, though I am basing that mostly on my own experience only: hot drinks in general can relieve some digestive symptoms, but they're better at getting things moving and easing cramps from constipation, they might not be good for diarrhoea.
Take it easy while on a liquid diet, and if things don't settle soon, consider consulting a doctor in case medication changes are needed as well.