I'm not a pro or anything but I shoot a lot of boxing. It's all I shoot, in fact. As someone said above, try to get some different angles. I get that that's not always possible and I know the score when it comes to camera placement at venues, but getting some footage through the ropes from a low angle will give you great footage. I've never done it, but a lot of amateur/unlicensed shows like this one (maybe White Collar?) don't care if you mount a Go Pro or something near the ring. Looks cool mounted near a corner of the ring. If I could pick two camera positions to make up the entirety of fight footage for promos it'd be handheld from through the ropes and shoulder mounted/handheld from the corner on a platform.

In terms of other things, I find minimal use of slo mo works to your advantage with these things. It looks cool for big hits and great defence but takes away from the excitement and speed you'd wanna associate with a boxing event. It does work really well for capturing fighter entrances to the ring though. Bang a light on your camera, go handheld and you'll get some stuff that looks really cool slowed down to mix in with fight footage. But yeah, try to be closer to the action and get some shots of the crowd having a good time if possible. That also looks good when promoting an event. Also not feeling the over use of shaky effects but that's just me. It's a bit disorientating and that kinda thing looks better when timed with hits.

I sound like I'm shitting on the video. I'm not. It's way better than a lot of the stuff I see around from boxing promotions. Just try to cover as many angles as possible and get as close to the action as you can. Keep it up man.