Well basically it depends on the context. for example gucken can be used in the following situation "Guck mal dort" --> Look over there! angucken is often linked with an object "Guckst du dir morgen das Fußballspiel an?" "Wir müssen uns unbedingt diesen Film angucken." "Guck dir das mal an!" However, the words "gucken" and "angucken" sound quite informal and not very elevated. You should better use sehen/ansehen or schauen/anschauen. At least that's my opinion.

sehen/gucken/schauen: plain optical activity with the eyes --> to look ansehen/angucken/anschauen: attentive focus of the eyes on something --> to look at, to watch

Das gleiche wie zwischen "sehen/schauen" und "ansehen/anschauen".