Rhinoceros is used most widely I guess and youtube is the best tutor.

But for different programs / schools, they might use different software to support their research. eg. grasshopper, maya, houdini, c4d.... there are too many.

If you can tell us what the program is, maybe you'll get more specific suggestions.

Depends on your grad program... but most schools you could get through with just Rhino and Illustrator. Photoshop would help, and grasshopper for rhino would be critical for some programs and totally optional for others.

100% start with Rhino.

A lot of universities are using Rhino / photoshop / illustrator combo but for me, if i had to do school over again, i would use Vectorworks (which my previous office sold me on). However, if you have no technical experience with programs, i would recommend that you feel around with sketchup to get the basics of 3d modeling and when you feel confident enough, switch over to "big boy" programs like Rhino.

In terms of the working profession, AutoCAD or Revit would be your best bet. But school =/= work so pick your poison. 

I resist learning software, I do nicely with a pencil, T-square and paper!

#Resistlearning software

For drafting and line work start with: autocad, illustrator.

For 3d modeling start with Sketchup (simplest and quickest, best for straight line masses) and Rhinoceros (easily adaptable with autocad and other softwares, better for more sophisticated curving designs. can also use plugin such as grasshopper later for getting a taste for parametric designs)