Google discworld reading order, pick a storyline that is similar to genres you like (the guard books are copper fiction, the Lipwig books are inverted heist novels, the Rincewind books are classic fantasy by way of Oxford University culture, etc.)

Just starting with the first book (The Colour of Magic) and continuing in release order is fine. No need to make things more complicated than that.

Start with the City Watch series of Discworld. If you like Guards! Guards! then you'll like the next books. After reading a couple of them I'd start branching into other series.