How Can I Clean and Free Up Storage Space On My Android Device

STEP 01
Photos backup
Backup Your Photos Online and save Your space.
STEP 02
Moving apps from device memory to the micro-SD card
Moving the apps from device storage to external micro-SD card storage
STEP 03
App Settings for media auto-download
Set Your installed Apps not to download any media files automatically.
STEP 04
Factory data reset
Reset Your Android device and remove the space used by unwanted files.
STEP 05
Other Necessary Settings
Cloud storage , Cache mechanisms, Apps to clear temporary files
01 .Photos backup
You can backup Your Photos Online and use it whenever needed.
How to Increase the space by Online Photo backup
Photos usually occupy the major portion of your devices' storage space. Each photos have their own size depending on the resolution set on your mobile camera. Taking Your photos online improves the performance of Your device and gives you more space. So the first step in freeing up space should be Photos backup.
Example
Google Photos app is an inbuilt or a default app that can be found on all the android devices. Google Photos backs up photos on the cloud automatically and allows you to delete the device copies and clear up space. The important feature is -- the photos, videos and albums on Google Photos can be accessed on any browser or any other dedicated mobile apps (accessed only by the account owner).
Google Photos app is a free app can also be found on the Play Store and comes directly from Google. Storage is also offered for free by Google (15 GB Google drive account). So You could also backup any “high quality” images and videos as you like.
02. Moving apps from device memory to the microSD card
Your device must have an external micro-SD to transfer the apps from device storge to external storage. I You have a SD card with lot of storage capacity (say..32GB)then you can store a pile of your apps there to be used whenever needed. By moving apps to external storage card the app data might be stored on your device, but the amount of space it takes is negligible.
After doing this whenever an app needs to store something on Your device such as media files - videos, audios, wave files, pdfs or others, they will be stored to external memory card. So now the primary memory is free and improves your phones (speed) performance.
03. Media auto-download Settings on Apps
Todays' digital world have a number of Instant Messaging Apps (IM apps). Being the populous among IM Apps, WhatsApp has more number of active users. WhatApp stores photos, videos and other content in installed devices. WhatsAppby default has the setting to auto download the content to the phone storage that are sent by your WhatsApp contacts.

However, this can be disabled by opening WhatsApp, heading over to Settings, tapping Chats and calls, then navigating to the Media auto-download setting. The media auto download controls the files downloaded to your phone automatically. Here, You need to select the No Media setting to save your data as well as boost internal storage space.
04. Factory data reset on Android Device
This step should be followed only when You need a full system cleanup. People using android devices have experienced, a factory data reset sometimes enhanced the performance of the device. By performing a factory reset the device is restored to its original state and also removes the unnecessary apps along with clogged files stored in the device memory and storage. You can reset your device anytime to factory settings by heading over to Settings - Backup and Reset and tapping Factory data reset.

Note that by resetting to Factory Settings, You can lose account information already stored (Google account) and other details stored by Apps.
05. Other Necessary Settings
Always try to store Your files online or Cloud. This could save a lot of Your Space. By saving online You files can also be secured and are accessible only by the account user. The modern day mobile use is through cloud and the next generation will have a Advanced Cloud Store and No external Card will be needed !!!.