like Mr. D said you would just have to make many mastercopies.
Do many thorough copies of the works you like. Use the same material (if you can get information about it). Judging from another field of art (music) that I am more proficient in, you will have to do this a lot and for a longer period of time to make this second nature.
After a time you will find that the traits and features of the style you studied have become second nature (and that you have become aware of them in the first place) and then you could try and wear your newly acquired mask while drawing/painting a design of your own.
But, again judging from what I learned in music and from observation with fellow musicians, after that initial success there’s a very hard period of shaking the mask off. I know people who spent months studying a guitar player’s style and then it took them years trying not to sound like the guy they studied. If they (and you) succeed, all of the blessings of this kind of study are yours to reap: a deeper understanding of the artist you love and a wider range of possible choices for artistic expression.
But if they failed (and I have seen it happen), they end up being a cheap mimicry of someone else struggling to get back to their own way of doing things.
I don’t want to sound like a mysterious porter at the mirror gates… heck, strike that… I actually do… so here goes…
beware, adventurer! The path can lead to both deep understanding and to the center of a maze in which you will spend a lifetime trying to get out. You are warned!
cue manical laughter