The current industry standard is MS Paint. All big-name firms demand this as an absolutely necessary skill. Start out with a few simple tutorials and then when you feel confident, move on to the highly advanced commands. Other students will tell you to learn "important" programs like CAD/Revit, but they're just wasting their time. No one cares about these toy apps. As far as gadgets go, you'll need to get an iPad(R) Pro(TM) for the best learning experience for your shiny new apps.