When in the middle of the night you will start to hear noises. Those are mobs. Mostly Hostile mobs will make noises.

Make a little or big house and be ready with a sword.

Zombies- When fighting zombies you just have to get close enough to hit them but no hit you. Some will be wearing armor, so be cautious and be prepared. Use splash potions of healing to harm zombies not harming potions. Baby zombies are fast and tough. They can ride chickens (2% chance) they can also spawn more.

Skeletons- STAY BACK... don't get too close or else they will shoot faster and faster. They will also get armor too. You still need healing potions to damage them. I suggest using a bow and have plenty of arrows.

Spiders- they suck whack them one or twice and they'll be no problem.

Creepers- All I have to say about these are hit them and back up and repeat until they die.

Nether Mobs- Make a cobblestone home and snipe with your bow. (ghasts cant destroy cobblestone with their charges)

Silverfish- Have a fast reaction to kill him

Or you can just go to sleep

You are now ready...