How do you optimize your hard drive? What means "others" in hard drive memory drive memory?

Hello

Someone knows what is the meaning of "others" when you see how is your hard drive memory used or occuped?

And how can you optimize the hard drive memory? i mean... i haven´t installed many programs in my computer but i see know 32 Gb used and named "others"... i don´t know what is it.

Thanks

jorge