While I knit fairly fast, what makes a bigger difference for me is finding extra time to knit. Taking advantage of those opportunities when a few moments present themselves.
I have a headset for my phone so that if I'm on the phone or on hold I can knit. A portable phone that clips to my pocket along with a headset is even better because I can go GET my yarn while on the phone
I wear things around the house with big enough pockets to hold a cake of yarn so that I can knit while waiting for things on the stove to heat. I always keep knitting in the car, you never know when you will be stuck somewhere, or waiting for someone.
Getting in the habit of using up those small amounts of time makes a bigger difference to how much knitting I get done than my speed dose.