Things to avoid
Protecting the screen with lamination:
We are not living in 2006 so are the phones. Now they use touch screen technology rather than physical buttons, so applying a lamination to your device would significantly decrease the touch sensitivity.
Rooting with Android apps:
Although the concept of rooting is not for normal users if you do root your device then root it with proper PC, not with Android apps. Because those apps could be malware or spyware. which could affect the performance of your device or hack your details.
Installing third party app killers:
Well this correct to some extent only. Installing third party app killers doesn’t make any sense as Android (after jelly bean) OS is already smart enough to stop unwanted background processes. Using third party app killers cause further battery drain rather than saving it as the apps get killed and restated over and over again. But on the other hand, first party app killers are effective and efficient in killing apps as they have device’s root access. also, the third party app killers spam your device with advertisements.
Splashing your phone in water:
yeah, I know this is quite obvious but there are phones which claim water proofing/resistant. But only trust that claim when the manufacturer says about IP certification (Ingress protection) for ex IP67. Also, take a look of IP certification system http://www.dsmt.com/resources/ip-rating-chart/