One of the most popular methods to revitalize your design is to listen to other games or other forms of media. As a designer, this research is critical. Sit down and listen to other games, preferably in an environment where you can listen at a good volume without too much external noise. As you listen, there are many aspects of the sound design to consider:
If you hear a sound you really like, spend some time with it. Listen critically, trying to dissect the sound into its individual components. As an exercise, I sometimes try to recreate the sound myself -- not to steal it, but as a way to inspire myself and generate my own ideas through the inspiration of someone else's design. This practice often points me to new techniques and ideas in my own design methodology.
Another thing to consider when listening to other games and media is to ask yourself what you would have done differently.
These exercises serve the important role of keeping your brain analytically limber so you can quickly and accurately assess the same issues in your game during production and into the final mix.
Very few games have near-perfect audio, and even games that are amazing can be critiqued. Given the power of hindsight and limitless time, the audio in any project can no doubt be improved. Listening critically and evaluating a game or movie's sounds can help give you ideas for your own needs.
Often we relegate our listening to games and movies within the same genre or period, but I suggest evaluating all pertinent media. If you're working on a space action game, listen to a sports game, and you will likely be surprised that there are ideas to be mined. When working on a real time strategy title, check out some first person shooters. There are sonic elements in every game which we may not be thinking about, yet can be co-opted, refined and applied to make our design stronger.
"Man's mind, once stretched by a new idea, never regains its original dimensions." - Oliver Wendell Holmes
Sometimes the best way to invigorate our design processes is by taking a step back into the past. Every project is a learning experience, and each game brings with it its own set of challenges, ideas, and a unique design aesthetic.
When I first started as a sound designer I was in awe. I could not believe people got paid to make sound for a living, let alone that I was now one of them. I took enormous pride in my work (and still do), and had the facilities available to me to capture and record much of my own sound. It was a time of experimentation and a lot of fun. Many of my ideas worked great, and some failed miserably. But I learned a great deal in those first few years about experimenting with the recording and manipulation of sounds to create appropriate effects.
A few years later, when I hit my first bout of designer's block, I began thinking back to those early days and remembered how excited I was and how much I enjoyed the pure creation of sounds. Reflecting back made me realize that in the current situation I had become so mired in unrealistic deadlines that I was no longer thinking like the creative designer I once was.
My work situation was a little less private (sound designers with headphones in cubicles!) and I became resigned more often to using our effects library and just tweaking those sounds, rather than creating my own custom sounds.
I made a concerted effort to start doing what I had always loved doing -- creating my own sounds whenever possible, which in turn made my design sound fresher and more original. I began taking the knowledge I had acquired over the past several years and reintegrated the wild creativity and fun that I started out with to form a much stronger base for my design methods.
About a year later, I began using various modes of synthesis to augment my sound design. During another stagnant-feeling period of my career, I went back and listened to those sounds. I recognized how some of the synthetic textures made the sounds stand out and gave them their own voice, while making them fit into the respective game world better.
So on my next project, I reinstituted this aspect of my old aesthetic, using new knowledge I had learned about synthesis and making the most of the new tools I had acquired. The result, again, was a stronger design in part due to reviewing past work.
In looking at our old projects, we can borrow our own best ideas, concepts, tricks and lessons learned from these past experiences and evolve our current methodologies by incorporating the best parts of what we used to do with the positive aspects of what we have learned since.
The point is that in all of our past work, there is an abundance of content that can help us in many different ways.