I personally prefer sensing auras (feeling the energy) or seing the colors of energy that is being emitted and surrounds the objects while my eyes are opened and calemd and able to concentrate very well.
However, I am aware of the fact that using a technique of seeing auras while the eyes are closed is very possible and useful if this is the best and most comfortable method for you. This can be done by a technique you need to perform, however it's not waht you think about. You will not just close your eyes and see the aura and it's colors without doing anything, like Hocuse Focus.
You basically need to do some exercises for that, practice, dedicate time, effort and patience. After you practice, you get to know how to perform the technique properly and then you can see auras of objects while your eyes are closed easily. But you will not achieve this by just closing your eyes and imagining thing.
For example, if you see them regulary, when you sink your brain's frequency, this should probably be the aura. But if you just press your eyeballs and see weird colors and so on, this is probably something different. Everything needs practice, it does not come immediately by closing your eyes.
But this is possible, as I said. You can close your eyes, Breath deeply a few times and imagine that there is a line of light connecting the center of your forehead with the same spot on an object. Ask yourself what colors and patterns are in the object's aura (it is better to use it on a friend or someone you know) You may have an inner image appear or simply a sense or feeling of what the aura must look like. Report what you have seen to your friend and correlate the colors/patterns with the emotion they were feeling.
Again, practice, practice and practice ;)
That's my input on this topic, lets see what other folks have to say about it.