go with the flow, art comes from you, it can not be copied and or sampled because you never do 100% same.
just pic up a pencil and think of a pic/google something
start small (fruit) <-- gai but trust you have to!
after a bit you will develop tone and shading, then move on to bigger pics
(if you done understand above, look at charcole paintings and look at the shadow and texture) or tut it lol
after that, move to were ever your pation lies, mine is in graffiti

if you need anything els, hit me up.
btw this go's for everything, i recommend this 1st then move to ms pain, photoshop (drawing-scan and edit)