Lack of Effective Communication and Challenge Discussions. When you are involved as a technical person leading model development in an optimization project, sometimes lack of communication between you and your clients can affect your model results and ultimately the applicability in real life. You miss one simple constraint and your results become impractical. This is especially true if you are new to the business and you have little experience of how the processes works on your client side.
In such cases, the best way is to ask as many questions as possible, even if they might feel naive to other people. Do not be afraid to use simple terminologies because its often the case that plant engineers or process engineers have little to no experience of operations research. Right effort at right time can save you from a lot of pain later.
Be open and be 100% prepared for the actual outcomes to deviate from what you see in your computer and not to succeed in your first few iterations while you would ideally expect to. Solving optimization problems on computer is one thing and bringing optimization models to life is another.