Well, I learned something about Minecraft. It doesn't play well with multi-core computers. So if you have a multi-core computer, Then here are some less lag tips.
1) Do ctrl+alt+delete
2) Open Minecraft
3) Click on processes
4) Right click on Javaw.exe or right click on Minecraft and click go to process
5) click set affinity and deselect all of your CPUs until there's only one checked
6) ENJOY!
Optional- You can set the priority to high as well to decrease lag.