Have you tried transcribing some of their playing? This isn't always the easiest way but in my experience it is by far the most effective. When I spend time transcribing a guitarists playing (or saxaphonist etc...) I feel like I can get inside their head and start to get a good idea on how they phrase things and approach their instrument in general.
learn their solos or playing or recording whatever you use to hear them

learn them by ear is the best choice
listen to their note choice
their phrasing
try improvising over similar music or maybe a backing track of their songs
I hope you know who I am talking about, but they both are in the stoner/doom band electric wizard and they're solos especially the second bluesy one on they're first song is what I want to be able to do
P.s the song is self titled electric wizard
You can't "improvise like someone", that's a silly notion. You can copy a player by playing their music, or you can improvise which is by definition YOU creating something on the spot using YOUR knowledge and YOUR experience of music. If you're consciously copying someone else then you're not improvising.

By all means learn about someone's playing style - learn their solos, learn how they construct them, learn about their phrasing and the theory behind them. Understanding what they do will help you recycle their ideas and use them in your own playing but you're still not going to be copying another player and you won't sound like them, you'll still sound like you.
Actually called Mark!

Quote by TNfootballfan62
People with a duck for their avatar always give good advice.

...it's a seagull

Quote by Dave_Mc
i wanna see a clip of a recto buying some groceries.