• Syllabus for GATE  and IES  is  almost same. don't take both as different things.
• Core  branch syllabus  is same for bot in IES  there will be subjective paper so you have to practice  for that also.
• In IES there is general ability and Current affairs  section is also besides that technical paper which means that you need to study arts field's also. so half an hour a day for that is sufficient.

Hi Mapmi

Congratulations for your clarity about yor future . You can refer to Time meterial. They generally have seperate package at their coaching centres and online as well .