Few things.. What game version are you using? I would suggest using the latest Minecraft version. If that doesn't fix it, try using Optifine. Perhaps the load on your graphics card is too much, and that's why it is rendering glitched textures. Optifine can help ease that load. Try reinstalling Minecraft by deleting your .minecraft folder located in roaming. Make sure to backup important data like world saves. What are texture pack(s) you using? If the above suggestion doesn't work try disabling the GTM texture pack and all other texture packs. If that works, that means it is possible that the GTM texture pack or other texture packs didn't load correctly/your graphics card are having trouble rendering it. If such is the case, manually install the GTM texture pack by using the link that shows up in chat when you type the command /rp in game. If that doesn't work, move on to the next bullet. Update your graphics card. There are great tutorials on how to do this online and can vary card to card. But you can search for "Device Manager," go under "Display Adapters," right-clicking your graphics driver, and clicking update (This is for windows only). Again, I would suggest looking it up though. If all else fails, I would suggest getting a new graphics card, since most graphical issues are linked directly to your graphics card.