PureShadow

Assuming you mean Resource Packs, which replaced Texture Packs back June 2013 with snapshot 13w24a for Minecraft version 1.6.1, it's very simple. First, you need to locate your Minecraft Resourcepack folder. By default, this is located at C:\Users\[Username]\AppData\Roaming\.minecraft\resourcepacks, however if your Minecraft folder is stored somewhere else you simply have to find your .minecraft folder. Inside you will find the resourcepacks folder. If you don't have a folder named that, simply make one.
I believe you can also do this in game by going to Resource Packs and then clicking the button to open the Resource pack folder.
Next up, put whatever Resource Pack you want into the folder. It's typically stored in a .rar or .zip file.
I can personally recommend the Faithful 32x32 Pack which aims to keep the Minecraft feel while also revamping the textures quite a bit. Sadly, this Pack is only updated to 1.8 as far as I can see, so you might find some errors.

After you've installed it, simply go to Minecraft, go to the Resource Packs and then select it. Your game might freeze for a few seconds but after that it should work.
Enjoy!