I would like to start off by describing the most common mistakes that occur when officers initiate contact with gangs. Please, do not go by old-school "I'm the law here" style of communicating. Yes, we're the police, we do have the authority. However, you must understand that in modern times strategies and methods of approach are not alike those 30 years ago.
From what I observed, the LAPD Officers have more of a "chill", but cautious approach. They're polite but demanding. Now, I am not saying that there isn't a single time when you should go aggressive or bossy, of course not. I'm just saying it shouldn't be by default.
The thumb rule is: LSPD/LSSD isn't a GANG, it's a law enforcement agency. And should be portrayed as such.
Neither. It is not your job to be friends with gang members nor to be their enemies. It became clear throughout the ages that this problem is like the drug war: it's nearly impossible to solve it. Thus it's more of a game of co-existence.
It is unlikely for a police officer to be friends with known (or any) gang members. Their worlds are just too different.
Same with being foes. There is a thin line between having IC motives of "fighting the crime and gangs" and policing the server. So if there is an option, let it be the neutral one.
Remember this: you are alone. Yes, you have a radio and maybe a dozen of officers on duty. However, they're not here with you. So when you find yourself thinking of "whether or not I should approach this gang/group of people", choose not to. It is not realistic to bluntly risk your life thinking "you'll handle it alone" or "I'm cool with them". One day you are having a chit-chat with a gang member, he seems "cool". The next day he shoots you in the back. Every officer knows that.
After all, if you absolutely do need to approach a group of people, remember what the Academy taught you: there's never enough backup. Do not engage/enter premises without sufficient backup. If we want criminal roleplayers to roleplay fear, we must do the same.