In the early game food and water can be a serious issue in Ark: Survival Evolved. Unless, of course, you know the basics, along with a few quick tips and tricks to make the most out of what you have!
Water is perhaps the easiest, yet most dangerous, of the two to aquire. In the beginning, before you have a Waterskin or Waterjar, you are stuck in the unusual position of having to submerge yourself for a drink. That's right, for some reason you can't just hand scoop water at this time. You actually have to go into the water until your are submerged and wait for your water gauge to fill. It doesn't take long, but it can easily take long enough to run into sharks or other waterborne predators.
The safest way to get water at this stage is to find an area along the coast that has rocks forming a bit of a protected area. Enough water that you can get submerged to drink, but surrounded by rocks that prevent predators from getting to you. Check out the screeshots below for a few good examples.
The problem with food is that it spoils quickly. Berries don't last long, nor does raw meat. Cooked meat lasts longer, but it still doesn't last that long. In the early stages, before you have any means of preservation, you'll have some trouble. Berries are probably your best bet at first for a truly reliable source of food.
For meat, your best bet is to cook it shortly after you get it. You don't really want it hanging around in your inventory for very long either. So hunt what you need when you're starting to need it and you won't run into too much waste or shortage. Ultimately, until you have either a Preservation cupboard or a Dino, keeping food is a short-term-only matter.
To store your food much longer you will have to look into one of two options. Later in the game you'll have more options, of course, and can even move into farming.
One of your first 'longer term' storage methods will be a Dino. That's right. Berries and such keep dramatically longer in a Dino's inventory. So if you've tamed a Dino you'll want to keep your food stored in its inventory to make sure it will last.
Another 'early game' option is the preservation cupboard. It requires Sparkpowder, but it does keep food edible much longer. To make Sparkpowder you'll need the Engram for it along with a Mortar & Pestle. It's made from 2 flints and 1 stone. That will give you 1 unit of Sparkpowder. You'll also need the Engram for the Preservation Cupboard. Keep in mind that while this is a bit of an adventure to setup, the Sparkpowder lasts a very long time in the Preservation Cupboard and food lasts dramatically longer too.