How do I become a sub-15 cuber?

Question

Right now, I can solve a Rubik's Cube with an average of 17 - 20 seconds. Sometimes, I may get 15 or 16 second and my record is 12. I am currently using the Fridrich method and below is how long I take to complete each step.

Cross: I almost always solve the white cross, and on rare occasions I may solve the yellow cross. The cross takes me 3 - 5 seconds to solve.

F2L: I am beginning to get good with look-ahead. The F2L takes me about 8 - 10 seconds to solve.

OLL: I currently know the 2-look OLL and I use ten algorithms for it. OLL takes me 2 - 3.5 seconds to solve.

PLL: I currently know the full PLL. The recognition and execution takes me 2 seconds to complete (except for the G-Perms which take me about 3 - 4 seconds to recognize and execute).

All I have been told to this point was to either learn full OLL (which I don't want to do right now because it won't help much) or practice look-ahead. Well, I have been always practicing look-ahead over and over and my times still haven't improved at all over the past several months.

Are there any tips or things I should do to become a sub-15 cuber?

Answer 1

You should start learning OLL's (I cases first, they are easier to memorize), except dot cases - IMHO - which could be cancelled with a sledge-hammer.
As for a long-term project, you should spend some time (a week?) solving without pausing between F2L pairs, even if you need to slow down to do that.
Eventually, you'll solve without pausing between F2Ls faster, and sub-15.

I should note that a average of 17-20 with basically just cross OLLs is pretty impressive.

Answer 2

The only way I could imagine getting an average under 15 seconds is practice practice practice until your brain absorbs all the patterns and that the next move comes to you naturally.