Beard growth completely depends on your genetics which is primarily the result of high testosterone.
You can not beat your genetics so the only option left with you is to live an active lifestyle along with some good diet which includes adequate amount of essential vitamins,minerals proteins and healthy fats. Having a good diet definitely results in the growth of your testosterone level which further accelerates beard growth too. A good composition of the micro and macro nutrients along with the usage of chemical free cosmetic products on your skin can definitely improve your skin and hair quality which plays an important role in beard growth.
In my case, My father never had a beard. Since i was 18, I use to shave once in every 4–5 days as i always wanted to grow a thick beard and shaving regularly to grow beard was a big misconception which was making rounds back in 2013–14.
I was fed up of my little goatee and was very desperate to grow a thicker beard. I ended up doing everything that i could do to achieve it untill i finally earned it.