Design Dilemma

Anybody who designs anything knows how difficult it can be to have a completely original product. This is even more so when you are designing a product for a market that has a very dominant product established. So, my current thinking has similar thought processes as one might have if they were in a corporation designing a product for market, but mine is for a class project.

My problem is deciding what is outright copying versus implementing ideas that I feel are very good. I can only think of the iPod (yes, so cliche) when this crosses my mind. The iPod was the first widely popular mass marked portable MP3 player that really took off with people. Yes, had to state the obvious. Now, there have been many new players into the market that the iPod created. This seems only logical, right? I mean, if you can tap only a little bit of the market share, you are bound to make a little money (pending product quality among other things). But, they had to build off what worked to even have a chance.

My problem is within the visual design of our project. I have tried to take the effort to take ideas I like and implement them in what I am doing. I have also tried to not “lift” designs from other products already out in the market. But, my main question is this, where is the line between stealing a design and implementing things that have just worked?