Oh gosh, that must be a terrible job for someone nice.. I think you're probably too caring and too 'nice'.. and they can sense it..
I agree with Kiwi, is there some sort of training you could go to, to improve your verbal and non-verbal communication? Maybe mediation or assertiveness training? (a good one)
For teaching, I was told you need to look MEAN the first time you meet them, 'like a terrorist' a good-looking teacher said, so they know you mean business! If you smile on first day, you may have problems all year long.. NO SMILING!! (sounds horrible for someone nice, who wants to help, I know!!) I was also told to 'dress up older', maybe you just look too young?
I'm guessing you must be 'strict but fair', now how to get to that...?
You are in a position of power, and you must understand that first. You are not there to be their 'friend' or to be 'nice'.. You need to be respected first, so they are disciplined enough and get what you tell them (and then maybe you can gradually be nicer, as they earn YOUR respect!!) It is a privilege to get the benefits you can give them, and they need to understand that.. Maybe you can watch some movies with 'strict, tough 'n' fair' characters...?
You also need friends in RL, and ideally a significant other... So you don't look for 'friends' and their acceptance there, on the job..
They need to respect you, if they like you, it's a bonus..
Maybe you had bad experience with people who criticised you or were 'tough' on you.. (I sure did.) It's important you realize being 'tough' can mean 'love' too..
The book 'Dealing with difficult People' gives some advice on how to deal with 'tanks' or 'granates' (people who explode) though a book or course for your context specifically would probably be better.. Have you looked if anything like that exists?
A waitress told me she told a guy who threatened to hit her, 'I hope you have a really rich Daddy' - he was confused and said, 'Why?' 'Because I'll sue you for ..." (insert equivalent for LOTS in your language) She was also told later on she 'looks really mean' and successfully scares kids too.. Do you know any waitresses who could teach you? (They must get used to dealing with drunks etc.)
Learn from the bigger black guys.. ask them privately what to say, how to deal with these kids.. Also ask other successful co-workers.. They may give you tips of great help.. What do they use, what language, what words exactly? What can they threaten them with (legally)? You are a person of great power to these kids. You need to understand that power. What are 'empty threats' and what are things you could really pull off? (If it's just an 'empty threat' and you don't mean it, they'll sense it..)
Also, always act as if you got mad before you actually get mad. That's a trick a teacher taught me. Don't wait till you actually get mad. By then they've pushed your button and they might enjoy seeing you frazzled. 'Nice' people often allow others to behave disrespectfully too long, and don't stop them when there is still time to make things better.. stop them at the first sign of disrespect and maybe say something like, 'Two people in this room are interested in your wellbeing, one is actually getting tired of this...' (That's from the book on Difficult People and it works too, it's explained better there..)
Or try to find a POSITIVE consequence.. 'Right after you (...do what you want from them..) we can start working on (...what they want/are interested in...)'
Some general tips on communication and acknowledging other people's feelings can probably help too.. (For me, books by Faber& Mazlish were very helpful, although they're for communicating with kids mostly.. Maybe that could work with these kids too? Also when brainstorming, it's good to make 'decision trees', what is likely to happen if something is done, etc. To make the kids think about likely consequences of their actions etc)
Understand you are a PARTNER to this kids, you can help them get better position in life.. You are not meaningless, you are important.. Even if they act out, they are actually scared of what you can pull off..
You need to show them you care about them, but in a tough way, so they respect you.. (not with smiling!)
If you're young and new to the job you also can't threaten them with stuff like 'old cats' who look mean enough or already have a 'reputation' can.. (You could perhaps make up a hubby with mad taekwondo skills or such and allude to him sometimes maybe? Not sure if that is wise though, probably better to ask a mentor or something, in a half-joking way?.. It did help to talk about 'big' friends or a partner with 'tough' hobbies like hammer-throwing or hunting rifles in some situations lol, like hitchhiking or too-interested romeos, nothing like you are experiencing though..)
It's perhaps good if you start martial arts too? (And of course take basic precautions like anonymous/unlisted phone etc.? You probably had a training on that?)
Otherwise, look for good jobs elsewhere?
Maybe you'd be a perfect person for some other job!!
