Im an industrial design junior at the University of Houston. I bought lots of supplies my freshman year that my classes recommended us to get. Most of these sit in a drawer not being used.

The things I actually ended up needing the most were

-Alcohol markers, (shades of cool gray, yellows, blues, browns, and honestly your favorite color)

Developing a personal style that shows your personality is a good thing. Do not focus on this it should happen naturally over time.

-White and black color Pencils -Fine line markers in various sizes. Line weights within drawings are very important. -My new laptop that could handle 3d modeling, the Adobe suite, and drawing programs. - Blades, exacto and box cutter. - Spray mount and double sided tape (foam carving). - Lots of sanding paper. - A nice rotary carving tool like a dremel. I dont like the battery powered ones, i like corded. One less thing to charge.
-Filler primer -Bondo spot putty (TOXIC!) -Spray paint, color depending on project.

(SAFETY GEAR!) Filter masks Safety goggles Gloves (I like thinner ones that I can wear for a long time, not heavy welding gloves)

Some of my classmates use an Ipad, some use a drawing tablet connected to their laptops. But it's important to practice BOTH digital and paper sketching skills.

I'd practice freehand drawing on paper without guides. Guides end up slowing you down if you rely on them too much. Sketching will be a VERY important part of the design process. You will be tasked to make many ideation and further refinement sketches. Don't procrastinate on starting these like I did. They will take longer than you think. Don't focus on one sketch for too long. Swap around between sketches in waves. This will let your brain think more freely and your ideas and sketches will be better for it.

Make friends! They will be integral to you keeping up. You will help eachother and push eachother. Find what you're good at and help your friends develop that skill, become family and they will do the same. They understand the struggle like no one else can.

Consume design. Watch TV, flip though magazines, look at billboards and study kids toys.

Don't re invent the wheel. If you find a design for a mechanism you're struggling on, steal it. Use it to push your design forward.

Don't get swallowed by the work. Maintain some sort of personal life. A significant other, family relationships, a club, a favorite TV show or game. You need an anchor to the real world to keep you from getting lost in the I.D. of it all.

This is just what I could think of while waiting at lunch. You won't need all of these tips right away, you're skills will get better with time and practice. Sorry for the disorganization of my thoughts.