When you go forward you will need an armor to defend you, I recommend the iron one (economic and durable), I also recommend that you always carry a bow and arrows for distant enemies. Continue digging and you will find the red stone ore (redstone, lapislazuli, gold and diamond, but do not use the gold to make objects of work, since the gold is soft and less durable than the iron, it is used for objects that work with energy (to get obsidian), sword (not bad, to kill monsters quickly) and depending on what you get you can make more objects, although I recommend doing as much as you want part of the armor only if you have diamonds.
Later you will make a portal to hell, which will explain how it is done, here you can find several materials that for me are very useful. potions
You have to start putting up defense for your houses, as mobs can be very annoying and if a disoriented creeper arrives you could be left homeless.
Your mines should be complete they are really dangerous areas. It is also useful to put trolleys to transport materials from your mines to your homes.More news: Modern Pocket Watches in Brand: Colibri, Material: Not Specified | eBay
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One recommendation is to start automating your activities with redstone circuits, as it is very useful for certain activities of which I will speak.
You must make a farm with all kinds of animals to always have food and other materials of these. Nor is it wrong to plant a cactus, which you can then use to make dyes or traps. Another thing that you should do is a trap for mobs, but not to prevent them from approaching you, but to reappear and die while getting your items.
You can also make a cobblestone generator (if you are a little vaguetes or you do not want to destroy your soil) and an obsidian (a profitable way to make obsidian close to home)
You should make a map, a compass and a clock, and when you think it is When you have powerful and enchanted weapons (most importantly the bow) you must go to the End to kill.