I've always shown people how to do this method of squeezing out toothpaste because it will save you money, in the end. If you don't believe me go out and check the prices/oz per tube of the standard toothpaste tubes and the new "easier" to use tubes. You will thank me later.
Thanks to Erik Lindemann for correcting me on the bottle/tube thingy!
Step 1: Starting from the End
Most of the time you will have toothpaste sitting in the very end, just use the corner of your sink (given you have a flat edge, you can also you a table) and the palm of you hand to flatten the tube out until you have enough of a flat end to grip.