Contrary to widespread belief, practice doesn't make perfect. Purposeful practice helps, but perfect practice makes perfect. For example, if you're not executing an off drive correctly (not necessarily by the coaching manual, little habits can creep in) or lifting in order to maximise the isolated muscle mass, you can do that for ever but it won't necessarily improve you significantly...
If you are planning on undertaking this exercise, you have to ensure that all practice is sport-specific, purposeful and 'SMARTER.' You have to set short, mid and long-term goals - all pros across all sports do. They need to be (see acronym) - Specific, Measurable, Attainable, Realistic, Time-Phased, Exciting and Recordable. IN other words, everything you do needs to evaluated, assessed and progressive, whilst remaining motivational.
I remember my Sports Psychology tutor, who went on to work with the US Olympic kayaking team being adamant that 10,000 hours of practice will make an elite athlete and I have to say he was very persuasive. I didn't totally agree and I'm not sure I do now (for what its worth!). I'm not sure that genetics plays a factor solely, but you also need to take into account social factors (upbringing, exposure to sport [who with, how often, quality of practice, both informal and structured] geographical location), growth spurts, which can be ascribed to genetics, to a point - diet, exercise, birth date, even sleep can be contributory to growth. I'm not sure how old you are but if you're older than 10, the odds are significantly against you. That's fact and there's no getting around that.
You should also read 'Bounce' by Matthew Syed - the chater on Kenyan athletes is particularly fascinating...