This was a show around Sabrina Spellman, who is a teenager that finds out at her 16th birthday that she is a witch and can use magic. The main strength of the show was the humor in both the dialogues themselves and the comedy talent of the actors.
It turns out that magic is an extremely dangerous thing. Not only many seemingly harmless spells can go awfully wrong, but also all kinds of secondary events such as a witch telling a mortal she is a witch, or a witch kissing a moral for the first time, can end in disaster.
Additionally, Sabrina has to grow up like every other girl, including having romances with various boys and men, most importantly the one with her first love Harvey. All of this is complicated very much by the fact she is a witch and things that are completely harmless to mortals, such has having two different boys being in love with her at the same time at valentines day, can be quite fatal to her.
The show peaked very high in the beginning, but later lost first slowly, then fast in quality, losing good characters and good actors for bad ones, down to the point of becoming mostly unwatchable for being overloaded with shallow jerk characters in the seventh and final season.