Setting up a successful survival world on a superflat world may seem like an impossible task. Even the most experienced players may crumble at the challenge of this barren world. Hopefully, this guide will point you in the right direction and help you thrive in this new environment.

Step 1: Raid a Village:

You're first goal on the superflat world should be to locate a village as soon as possible. If you can see a village from your initial spawn point, make a beeline towards it. If not, head off in any direction and you are sure to eventually find one.
Once you do find a village, head straight for the blacksmith. Chests found in blacksmiths contain a multitude of useful items such as tools, armor, food and ores.
Next, harvest the nearby farms to gain a supply of carrots, potatoes, wheat and seeds. As there are plenty of farms in a village, you should have more than enough to feed yourself and start a farm if necessary. Wheat will likely be one of the most valuable resources in a superflat world. Along with providing a stable food supply, it can be used for breeding and trading. Through trading you can require virtually everything you will ever need in your superflat world.
Your final step in the village should be to take apart the houses for wood and cobblestone. Do not worry too much about preserving villages as it will be a necessity in the beginning to tear them down for resources.
Alternatively, if you have the supplies, you can get 3 buckets. Fill two buckets of water for an infinite water spring and one for lava. This will allow you to make a simple cobblestone generator.

Step 2: Mobs:

Mobs, as annoying as they may be to come across, will be an important part of resource collection. Some may provide a source of food (zombies, spiders) others may provide rare resources (witches). You will gain a large multitude of resources from these mobs. In order to exploit this you can either build a spawner or fight the mobs during the night. Building a spawner would be relatively easy once you have the required material as you do not have to go through the process of lighting up cave systems.

Step 3: Heading off:

Once you reach a point where you have enough supplies, you are faced with a difficult decision. Do you continue moving region to region (nomadic), or do you settle down (sedentary)?
Nomadic: Living a nomadic lifestyle will allow you to easily obtain valuable non-renewable resources such as iron and diamonds. However, several basic necessities such as wood will become much more difficulty to obtain a steady supply of. Choosing this type of life style will generally lead to you visiting each village no more than once. This being the case, feel free to take as many resources as you can from the village. Pillage houses, raid blacksmiths and loot farms.
You are also likely to come across more mobs than someone living a sedentary life style. Due to the abundance of slimes you will come across, making an enchanting table would be a relatively good and easy choice for you. Kill zombies for iron and a renewable supply of rotten flesh. Gearing up for battle situations will become a must. The abundance of mobs you will come across will also allow you to make leads easily. This can be a good choice if you wish to bring a small herd of animals with you as a supply for food and other accommodations. Alternatively you could get Donkey which would allow you to bring more items with you and travel at quicker pace
Sedentary: If you choose this lifestyle, you focus on harvesting renewable resources. You also have the freedom of focusing on trading and expanding villages in order to make successful permanent settlements. Trading is a great way of potentially finding valuable resources, although it can be more tedious.
The key renewable resources you will be after are wheat, cobblestone, wood and iron. Wheat is relatively simple to harvest as farms are usually set up for you. Getting a renewable supply of wood will require you to get saplings from a blacksmith. Getting a renewable supply of cobblestone will require you to get a cobblestone generator up and running. Iron however will likely require you to expand your village or make a farm to get iron golems spawning.
You will also want to avoid tearing apart homes if you want to keep your villagers safe. Perhaps you may want to dwell in creating a defence such as a wall around your village.

Step 4: We Need to Go Deeper:

It is entirely possible to reach the nether in a superflat world. Obsidian is easily found in blacksmith chests or alternatively made with lava and water fund in villages. The Nether opens up a wide variety of resources such as potion ingredients, gold and even the possibility of a wither fight. Wither skeletons and blazes can also be slain to gather fiel for furnaces. However, you want to ensure that you are well equipped before braving on the Nether.

Step 5: Fishing?:

That's right, fishing. A pool can be made relatively easily once you obtain an infinite water spring. Fishing rods are also easily made from mob drops and wood. Now fishing is more or less used for obtaining luxury items such as saddles and name tags. However, if you are desperate for a food supply; fishing is always an easy alternative. You can also get plenty of other equipment such as enchanted gear, sticks, string, enchanted books and lily pads!