Another building products designer/manufacturer here. I'm not sure there is a substitute for practice. I always have a large sketch pad on hand for working out ideas. I think you would benefit from giving yourself design challenges. For me design is about constraints.
1. Cut out a random convex pattern from paper and figure how many of that shape you can get from a piece of paper. Then figure out how you would have to alter it or separate it so as to maximize the number of pieces you could get from a single sheet of paper. How many more did you get from the sheet?
2. Sketch repeating patterns or scribbles on paper and look for meta patterns or get inspiration from one aspect of the pattern that makes you see something else.
3. Estimate how long of a strip of paper you would need to wrap around a cup or a block of legos. Then cut that length out and compare to the actual size to see how well you did. Compare that length to the width or height of the paper you cut it from. Will it divide evenly? Calculate the diameter from the length of the cup wrap or area of the legos.
4. Learn to layout true length triangles
5. Sketch products interesting to you on paper and consider their size and what shape that material would take if you flattened it out. Can you make it all in one piece? See if you can make small alterations to the dimensions to get more out of the material.
6. Take those sketches and try to fit them in a 'golden' ratio, see how close you came.
IMO, learning to find THE meaningful constraints is a key to getting good at design.
1. Cut out a random convex pattern from paper and figure how many of that shape you can get from a piece of paper. Then figure out how you would have to alter it or separate it so as to maximize the number of pieces you could get from a single sheet of paper. How many more did you get from the sheet?
2. Sketch repeating patterns or scribbles on paper and look for meta patterns or get inspiration from one aspect of the pattern that makes you see something else.
3. Estimate how long of a strip of paper you would need to wrap around a cup or a block of legos. Then cut that length out and compare to the actual size to see how well you did. Compare that length to the width or height of the paper you cut it from. Will it divide evenly? Calculate the diameter from the length of the cup wrap or area of the legos.
4. Learn to layout true length triangles
5. Sketch products interesting to you on paper and consider their size and what shape that material would take if you flattened it out. Can you make it all in one piece? See if you can make small alterations to the dimensions to get more out of the material.
6. Take those sketches and try to fit them in a 'golden' ratio, see how close you came.
IMO, learning to find THE meaningful constraints is a key to getting good at design.