Developing a new product can be a complicated and lengthy task. Complexity+time = a more expensive process. Speed is crucial in making sure costs don't get out of hand. So how do you speed up the process without losing too much quality during the development and in the end product?
Early planning is everything
Experienced project planners and leaders know that careful planning during the early stages of the project is crucial in making sure the project is holding up as expected in the end stages and costs don't run away. More and better early planning and defining of the project means less changes and extra costs later in the project. It might be tempting to eagerly start working on that cool design or those innovative ideas right away, but giving some time early on for proper project planning will always be worthwhile in the end. For example, when making a new product, there needs to be a defined end goal, a project time frame with preferably some room for later changes, a general starting direction and initial idea of how and what the product should be. It's good if there's data over some details such as overall material choices and suppliers from the start. Can it be made from standard parts or does it have to have a unique design? Is the technology for it available? Are there suppliers nearby? Some suppliers nearby might be somewhat more expensive than others further away but they might still be a good choice because of the time saved in using them, thus also saving costs in the end. Picking the right supplier is crucial for a quick prototype development. It's bad if there's only one supplier for a certain part and that supplier can't deliver the part fast.
Stick to it, but make sure to cover all angles
When designing and constructing the product make sure every detail's design follows the overall definition of the project. You don't want a small detail to be overlooked and ruin the overall result. Get a second opinion/review by another designer or engineer before making the final drawings. In the end it's up to the responsible designer and/or engineer to make the final decisions, so make sure you know what you do and be able to take responsibility for it. Don't be too afraid to make fast decisions, with experience this will come more natural, but never make any irrational decisions. Every decision, whatever it is, should be made consciously. Waiting too long to make decisions or making too many changes will delay the project too much. Getting it right the first time will save a huge amount of time and cost in the end.
Automate it
To further speed up the process, when constructing in CAD for example, use automation to speed up the workflow. Use a library of standard parts that are often used, use short commands and maybe some scripts. Many suppliers also have CAD files available online of their parts so that you get the article numbers and of course the size correctly in the CAD program. If you get stuck on how to make something in the program or something else you're not sure about, get help immediately. Don't wait too long, it's better to be humble and ask than to be stubborn and try over and over for too long. Find the right person within the engineering team to help you. Make sure there is a design routine for everything and follow it. Having standard routines can of course greatly speed up the process and making sure nothing is forgotten.