For those that do not watch the videos...Cops who get anonymous tips will use a technique called knock and talk or tap and rap. They knock on the door and if you answer they will not let you shut the door. They will try to come in to talk. All they need is to see or smell probable cause to come in, and anybody who is growing is screwed at this point. The cops then use all sorts of threats like prosecution of spouse and foster care to get people to sign consent to search. They act like it's cool since you are cooperating as they collect the evidence, then just before leaving, hook you up and take you with them.
The fact that they are knocking shows they have no right to come in. Do not open the door and step out...they will not let you. Go to a window and tell them you do not open the door for police, but the dispatcher could call the house phone, or talk through window.
If they have a warrant, show them your hands and tell them to kick in the door...they are trigger happy. They are drug addicts (adrenaline) and are doing this merely for the high...no joke.
Then beyond that, the standard advise would be, do not talk to police use your 4th amendment rights...we are at war...name, rank and serial number and nothing more but asking to leave or be left alone...everything you say will be twisted and used against you.