Step 1.) Download the Minecraft HD Texture Patcher
Step 2.) Run the Patcher EXE file and click the Patch button toward the bottom.
Step 3.) Download the LB Photo Realism x64 Texture Pack (leave this file zipped, do not extract)
Step 4.) Press WindowsKey-R and type %appdata%, hit ENTER
Step 5.) Navigate to “appdata/.minecraft/Texture Packs” and move the downloaded Texture Pack (zipped file) from above to this folder.
Step 6.) Run Minecraft and click Textures and Mods
Step 7.) Select the HD Texture from the list (this may freeze your game for a minute while it applies)
Step 8.) Click DONE and play the game!
NOTE: If this causes your game to display a black screen, you probably missed a step, repeat steps 1-8 above or delete the zipped texture from your appdata/.minecraft/Texture Packs folder to change back to the default texture.