I think I understand point 2 liao. Never take as much breath as you can hold. It is about taking the right amount of breath. Example, if got long break/rest, take more breath. If short breat/rest, take a quick breath (using mouth). So, gotta be familiar where are those break/rest and whether they are long break/rest or short one. After know it, gotta practice much too.
If want to sing pop song, need to use a pencil to right note the break/rest because no song sheet ma.