You seem to have the Rubik's Cube down, you can solve it like no other, but you're not fast. This video tutorial will help you become a faster Rubik's Cube speedcuber with a few tricks and techniques.
If you are a beginner, there will be some things you might not understand yet, and
that's okay, don't freak out, your time will come, just follow down the following list of things to learn and you will be speedcubing in no time. Don't forget, lubrication is a key factor is speedsolving too.
Your journey to sub-15 second Rubiks Cube averages:
1: Beginner's Method
2: Keyhole Method
3: 2-look OLL
3b: 2-look PLL
7: Advanced F2L