First thing I do is look into any other similar products and the users of those products. Some people write it down and categorize it, create spreadsheets and graphs, and quantify every detail. I have done this, and, it works, but it makes my head want to explode. Right out of school I worked on a project about office supplies that had this unbelievably gigantic Microsoft Excel file that we would fill out after gathering information through interviews and surveys. The project was cancelled and the information was unused. Hours and hours of research for nothing, quite literally. Luckily, I get to mostly choose my own path, so I do research how I feel comfortable. My research method can be described as "empathetic immersion". This is a phrase I came up with to describe what I do. Others may do the same thing, but the phrase is my own. Basically it means I put myself into the world of the user I want to design for. In this case, it was pens. Luckily for me I live in the age of the internet and I can sit down and absorb all the banter and visual stimulation associated with any subject without leaving my chair. I am able to get excited about what they get excited about. I am able to think the way they think. It could be camping equipment, it could be furniture, it doesn't matter. I become just like them. I really enjoy it, and I learn a lot in the process. I start to make decisions on what my ideal product would be. I let all of this information brew in my brain and then I put pen to paper.
I always got in trouble in design school because I was lousy at showing the process of how I arrived at a certain conclusion. If you are getting paid by a client/boss they want to see how you think. It doesn't matter if you know how you got there, they want you to lead them there with you. I have a hard time doing this because I am always at the next step and don't want to wait for them to catch up. I already asked "what if" about a half a million times.
So, I start sketching.
I kept sketching.
Then the clip.
Not quite there.
So, I moved on.
3D Modeling -
As soon as I find a design that I like well enough, I move into 3D to see if it will work. I started with a nib assembly I obtained and started designing around that. I made sure everything fit in the virtual world. I talked to the guys in the shop. We discussed thread pitch, diameters, and finally got it sorted. So I produced a design that could then be prototyped.
That, as it turns out, looked really, really good, and didn't make the pens too heavy. This was a win all the way around. But, could we also anodize the bodies and caps, allowing the clip and hardware to pop, and showcase the grip sections? Would this look weird?
Most of the hard lifting for the design work is at the beginning, once the project gets rolling, the goal is easier to focus on. A lot less "what if" happens and ideas become fewer and more directed. The choice to add rollerball functionality, copper and brass grip sections and even offering all the colors kind of naturally fell into place after all of the other decisions were made. This is obviously a complete and total simplification of the entire process, but it gets the idea across. In the end, you hopefully get something close to what you were originally aiming for. Sometimes you get something better.