What should I do before I try advanced troubleshooting Are there any generic troubleshooting steps and tips to be followed before I search for problem specific troubleshooting options? Then what are they? 

I only have a general knowledge on Android and not familiar with flashing, shell commands, etc.
There are several steps/things you can do before you do advanced troubleshooting. Most of the problems can be solved following these steps.


Backup your data. Backup your data first (of course, if possible). You don't need to risk it. Keep it somewhere else. It is better to have backups for personal data and app data separately.
Try rebooting your device. You can use your power key or a third party reboot app
Keep your device switched off for a while. Make sure you remove your SIM card (and the battery and SD card as well, if they are detachable) and wait about 30 minutes.
Try freeing some space. You must always have some free space. It is better to have more than 50MB free so that the apps can work smoothly. (Some say it should be 2% of total memory)
Try re-installing apps. If you believe your problem is caused by a specific app, try uninstalling and re-installing that app. Also you can try clearing the app cache. It will give you some more space.
No hardware fixes. Do not attempt to quick hardware fixes unless you have clear understanding of what you're doing. And keep in mind that you'll lose your manufacturer's warranty by doing such fixes.
Update your OS. Make sure that the relevant updates are compatible with your device, referring to your manufacturer's website.


If you are still in the problem, you can try searching help for your problem or contacting your manufacturer's customer support personnel. Remember to do this before you go to factory resets.