See... In isomerism... Note down main things like
Their definition of the imp ones like taoutomer ,metamer, optical.
Stability of keto enol in other page of taoutomer
Then e/z form rules, property of cos and trans, conformation isomer and it's types : sawhorse ,newmann then it's property like torsional strain,angle strain,etc.
Then very important subtopic conformation of cyclohexane,its chair form flipping,diaxial interaction then about optical isomer ,chiral centre,etc
D,L and R,S config.. flying wedge and Fischer projectiin
Enantiomers,diastereomers their characters and how to identify them etc
PS just note down things that you tend to forget in this topic and that are very important and asked