Done it to help friends or community, done it at my tournaments and explained to people what I would expect from a referee. Thankless job, I can't enjoy it but it doesn't ruin my day to do it.

You'll have good calls and bad calls, it's normal. Own mistakes and calmly talk to people.

Most common situations:
1) somebody disagree with your call but you know you're right ---> you are the referee, you are there to help and not to ruin other people's day, you know what and why you did. You don't have to explain yourself for every call or one week after you'll still be there talking to angry parents. Smile, greet, move to the next match.
2) somebody disagree with you and they are actually right ---Y sorry, it happens, we make mistakes. You are the referee, you are there to help and not to ruin other people's day. You are not a robot. Apologies. Smile, greet, move to the next match.

It's actually that easy :)

Episodes to share.

I was refereeing at my own tournament, with a set of rules I created. A guy who can not stand that he or his friends are losing yelled at me because I did not call points for an action. That action gives no points under those rules. Guy still wanted to be right.

I was coaching my girlfriend at one tournament. She was one point ahead until the last second, when her opponent scored exactly when the time ended. They were now at even points and the referee decision went to her opponent, with disapproving calls from many people watching. I asked why he did that call, he said it was a close match. No it wasn't I told him, my athlete was ahead until literally the last second and you are giving a match to the other girl for a point she scored at the very last second, are you her boyfriend? He lowered his eyes and did not answer.

I was refereeing at a friend's tournament. It was the final and I completely overlooked to give points for a sweep. The girl lost the final for that. I apologised and I really meant it, I was so sorry, but you can not undo your mistakes. Very poor call from my side.

Same.

I referred shooto/ mma and adcc for 10 years...

It was a responsability and i really enjoy it....
I was able to do the job so i did not want some incompetent people doing it.. i do not know if my english is good enough to explain this...but i saw so many people Who where not able to do it correctly, i decided to jump in

Politics ans federational bullshit/drama made me stop... not the badcalling badcalls or the athletes behaviors...i was used to it...and i often understand them because i compete myself.

Crazy stories:

It was a female mma fight...and one of them show off one of her tits to disturb the opponent to jab her on the face.... i didn't expect that at all...but i advertise her!
So vicious...

I will do it on occasion but it do not enjoy it.. But I much prefer grappling to fighting as a reff

as an advise?

try do begin ref with beginners, things are less complicated, slower and there is less "consequence" if you mistake..

when your confidence grow, you try some advanced level.

also, watching referees doing the job (good ones) is interresting ..... i almost learn mma refereeing by watching japanese pride and shooto referees working

I'm not sure about this.

I am almost a full-time ref, I do a lot of competitions as an official, and for me personally, it's a lot easier to officiate higher level matches, than beginners.

not in my experience.

but me may live it differently...

I haven't refereed BJJ specifically outside of in-house tournaments, but am a regional level referee for judo (or was? It's been awhile). It's always stressful. I'm always worried about making the wrong calls. Having said that, you get the best seat in the house to watch the match and as long as you call it like you see it and work to improve your ability to discern the action by watching a lot of matches (including watching how other referees make calls in matches that show them), there's not much else to be done.