Tips 3: Your 1st initial of LR process should be tru 600-800 articles/paper/books (various source) which called the process of 'Bird eye scanning' before you focus to 200-300 articles to narrow it down. The big wave of LR process usually happened between 4-6 times along the PhD journey.
Tips 4: Find only the expert in the area that u want to be good at, so that u'll save your time i.e: not everyone expert in critical writing in LR, n will b others expert in RM or analysis or concuclusion writing. So go seek the expert advice, everyone hv their own talent n advantage.