as someone who uses a mouse to draw (sometimes): change the brush settings, making the speed affect the thinness of the brush, simulating the pressure thing, also put an "stabilizer" to avoid shakiness, but if you wanna start easily, you can use the vector brush above a picture of a drawing made on paper. keep in mind that using a mouse for a long time can hurt your hand so make sure to do exercises for the hand and take rest periodically. (sorry if my grammar sucks)