Minecraft wiki entry for Hardcore_mode, associated text: In Video Settings, set brightness to "bright" to make things a bit easier, or "moody" for greater difficulty.
Use sound. Listen to everything; Creepers make sounds walking on blocks. Parrots can be even more useful for those purposes.
Even if you do have sounds turned on, use subtitles; they can alert the player if any sounds are nearby.
Avoid using unfamiliar resource packs. Sometimes it can be very beneficial to get a resource pack that changes certain textures slightly (for example, by slightly brightening the nether brick texture it becomes more obvious where it is safe to step in nether fortresses), but you should get used to the textures in regular survival first.
Turn on hitboxes. It can be very useful to see monsters in the dark.
By picking the seed (instead of using a random seed), the world can be controlled. This can vary the difficulty in many ways.