@Piedpiper
as you have already understood ...buy low ..sell high principle....try some mock trading first for one month.
whenever you feel some stock price is low ...you write on a piece of paper .... buy price , buy quantity and date.
Next whenever you feel stock price is high ...you write sale price , sale quantity and date .
Try 20 such trades without involving real money.
at the end of the month see what is your profit....if you perform well ....then go ahead with real money