How to run android phone flawlessly ?
Memory management: do not use any task killer, Android takes care of it well. Killing apps only waste battery when they have to be respawned.

Rooting the phone does help - you can weed out all the useless carrier and OEM bloat. Also, after using a bunch of droids over the past few years, I'd say modified, cleaner versions of stock ROMs >>> custom ROMs in terms of stability and battery life, with the sole exception being Nexus devices.

Learning to tweak and perfect Android is like doing it with Linux distros on PCs and servers - there is always more, it is a never ending process and we are all learning. There is no definitive list or article, really.

And most important, don't accept others' advice without thinking about or questioning it.