How to efficiently find diamonds.
In this tutorial, I will tell you how to efficiently find diamonds in Minecraft Survival. First, you will need proper tools - break a few trees and get a lot of wood, make a crafting table and some sticks. On the surface, find animals or a village or any source of food. Make sure you grab enough so you do not get stuck underground or starve to death. Next, find a small cave on the surface and get a furnace and 3 iron ore, use coal ore wood to smelt the iron and use them to craft an iron pickaxe. After a few minutes of mining you should be able to get an iron pickaxe easily, when you do that either find a cave or dig down to Y:11. Y:11 is the place diamonds are most commonly found, but it does not matter if you want to go one or two blocks higher or lower. Just note diamonds can only be found at Y:16 or lower, however the most common areas to find diamonds is around Y:5-11, if you find any extra ores such as iron/gold, make use of your time by smelting them in your furnaces while your mining to save time.
Once you've dug down, mine in a straight line (Stripmining). While mining in a straight line be sure to add small poke-holes to make sure you don't miss any diamonds or even other ores. By pressing F3 you can see your C counter on the left which tells you how many air blocks are in front of you; meaning the higher the number, the higher the chance of a cave in the direction your facing. If you think theres a cave I would recommend exploring it as around lava pits diamonds are commonly found there some diamonds or gold. Before going into the cave make sure to take note of where your furnaces were if not take them with you. If the cave goes up, make sure to stay around diamond level and not stripmine above it. Place torches in the caves to mark where you have explored in it if you want, this usually helps me a lot. Instead of that you can also get a fullbright resource pack to lighten up caves which is also another very useful thing to have. Just search on YouTube or your browser, "Minecraft lightmap texture pack."
You may want to turn directions to find which side is most likely containing a cave in front of it. Keep Stripmining until you have found a cave because you may want to explore it instead, if after a while of searching in the cave and it is not worthy, you can always go back to Stripmining. I use this strategy whenever I'm in need of diamonds or just want more, I think it is very useful from my success. However, sometimes you may not find any which is okay as I've experienced that before, I just continue mining or changing my direction. Take note of your durability, when you see the pickaxe you have is about to break, switch to a new one or make an extra one before it does so that you will not be trapped or have to waste sticks for a stone pickaxe. If you use both of them until a low durability, you can combine them in the crafting menu in your player inventory to increase its total durability, to increase it further, use an anvil and combine the pickaxes, take note that it does also cost experience. Besides that I don't have anything else to say, good luck mining.