These are all experiences during some years I work on spying filed with mobile phone (I will write in other articles about spying on PC/laptop. Here just for spying/tracking an Android device).
1. Legal issue:
You should consider if you track a smart phone, it is allowed to do that in your country/region?
For example, you are the boss and you want to track your employees? or you want to track your children? It is legal in some countries.
2. What spy app?
There are 10 acceptable apps in the world. You should choose the best one. It depends on what feature supported, the prices...
3. Physical access to install
a) A physical access of 5 minutes is required for the installation.
You must keep in your hand the target device, and the open browse to download APK file in case you want to track the Android device (phone or tablet). Or you must open Cydia app (with jailbroken device) and add source of the target app, and then install it in case you want to track an iOS device.
b) You should configure the essential settings on the target device.
Because the target app works silently in background, you need to configure some essential settings (options) in your target device to make it work for a long time. If not, the app maybe works some days and suddenly stop working. For example, with option Save battery mode of Android, when you choose Yes (turned on), it will stop the app to save the battery.
c) Clear the history of downloading/installing
After installing and configuring all, you should clear the 'history' of what you did on the target phone.
- Clear/Remove downloaded file.
With Android you can remove the APK file in folder "Downloads".
With iOS you can remove the source in Cydia app.
- Clear URL website where you visited to understand about the product. For example about features, about the prices...
- Clean URL website where you visit to download the app. Please remember that some products, the main site is different to the download site.