My interpretation of your post is that you are looking at the Storage menu in Settings, and seeing quite a chunk allocated to something called 'Other', and you want to know what that is and whether you can reduce it?
If so, it's probably dominated by your system software (actually by the size of the partitions the system software is stored in). Different phones use different names for this in the Storage menu: I've not met 'Other' before, but my previous phone called it 'System and Other'. Many phones just call it 'Misc' or 'Miscellanious', which is equally as unhelpful as 'Other'. My current phone actually calls it 'System'. But in all cases it's either completely or mainly the system partitions, which is also why you can't access it(*).
The problem is that your phone only has 8GB storage in total, and after you take out the operating system, drivers, baseband firmware, system cache partition etc I would guess that leaves you 4GB at most. There is nothing you can do about that, apart from move apps to SD where you can, keep all of your media on the removable SD card, and next time buy a phone with more storage. 8GB is really too little unless you are only going to use the phone very lightly.
(*) Actually you could access it if the device was rooted, but it wouldn't help: the storage your files and apps can use is the /data partition, and that wouldn't get any larger if you removed files from the system partitions. However removing stuff from the system partitions, unless you know what you are doing, is very likely to break the phone, which is why Android does not give the user that access.
