Rules of minecraft

Quoted From Minecraft Wiki
"

• Never break the block you are standing on unless you are certain what is beneath it is safe.

The general rule, especially for new players, is never to break the block your standing on unless you are coming down from a pillar jump. Breaking the block you are standing on causes you to fall, often into lava, a deep cave, water, mob-infested dungeon and occasionally (situations like The End, Creative mode and custom maps like Skyblock), The Void. Digging straight down is the only way to commit suicide in Creative mode.

• Never break a block directly over your head. Stand at least one block aside.

These two rules will save you from most "bust out" situations where you emerge from solid material into fluid or air. Breaking over your head invites flooding yourself with lava, water, sand or gravel.

• Have an "emergency blocking material" close at hand, and practice quickly selecting and placing it between yourself and unexpected danger (lava, water, and hostile mobs.)

The most likely such material is Cobblestone which has a great combination of abundance (mining stone drops it), butdirt, sandstone, and glass can work as well. Never use wood, as it can catch fire when used to protect against lava, and also has very poor blast resistance against the Creeper

• The other aspect of mining safely is not to lose your mined item drops.

The easiest way to lose item drops early in the game is to mine with an inappropriate tool. Wooden pickaxes can only break stone and coal ore. Stone pickaxes are required to mine iron. The general rule of thumb is that if it is taking longer than a few seconds to break the block, you are probably using a poor tool and the block won't drop the item. Iron pickaxes can mine everything except obsidian, which requires a diamond pickaxe.

If you encounter a high value block, such as emerald ore, diamond ore, or gold ore, mine around it to see what all six facings are before breaking it to ensure that you won't lose it in unseen lava. If this is done, you can confidently stand on it while you break it. Obsidian is a particularly hairy block to mine because it often has lava right next to or underneath it. The safest way for a beginner to mine obsidian is to capture lava in a bucket and convert it in a processing pool known to be only one block deep."