Ideal Process in Three Steps:
#1 Define the Problem
Clearly define the problem early on to guarantee a successful solution. The assumed solution at the onset is rarely the best solution in the end. Everyone involved needs to be aligned on the problem you're trying to solve and the goal you're trying to achieve. As a designer at this stage, it's my job to ask why and how a lot.
#2 Map the process
A mutual understanding of the process will assure success. What will collaborating actually look like? What resources will be available?What kind of work is best done together and what kind of work should I develop on my own for a day? Knowing when to seek feedback and work towards buy-in requires reading the room. No matter what, collaborating early allows for a greater sense ownership throughout the process.
#3 Align on the Solution
Good solutions map 100% back to the problem defined in step 1. The solution will likely fold in a mix of proven and novel design patterns validated by user testing. At the same time, the best design should go beyond and... DELIGHT. There, I said it. Cheesy, but true.
It's a lot of work — good thing I love it 98% of the time! Of course, the design process rarely follows this ideal path. Even so, keeping this process in mind as a north star, is still valuable.