Inventors must always have a firm grasp of the things they want to do. That is why it is crucial that once you have a concept in mind, you do your best to take that idea further.
You must understand that just because you thought of something great does not mean that you were the first to do so. That is why research is the first thing you have to do. This is pretty basic. For instance, you can simply look it up online to see if there are any matches. You can also look at those big retail stores to see if they are carrying any products that may seem similar to the one you have in mind. Finally, you have to check with the patent office if there is an existing patent on that particular idea.
If everything checks out, then you can go ahead and develop it further. If not, then do not be discouraged. It just means that your mind was on the right track. That being said, it is just a matter of time before another brilliant idea comes along. So just keep doing what you’re doing.