At the start, you have to depend on luck. Spam the right, down, left, A, S, and D keys. If you die it's okay, only stop when you're up to the 512 tile. That makes the exit time for the 512 tile ~20 seconds.

Then, use the traditional method you use (I use the one where it looks like a snake), but if your 512 tile is in the bottom two middle tiles, do the reversed snake method on the longer side, not the side with only one tile that's not the 512 tile.

When you're at the end, pick up your pace a little, if your mind sees that the tiles might add to 2048, spam it. From the 3rd row <--, then the 2nd row --> then the last row. <-- (The direction is flipped if your biggest tile is in the bottom left corner.