If you are the type of person that tends to kick up sand, then work hard on your buoyancy before taking the camera in the water again. Flailing fins not only fills your own photos with backscatter, it also endangers any marine life that is unfortunate enough to be in the way and ruins things for your fellow divers, who are likely to see just a cloud of sand instead of a rare and interesting critter.
It's satisfying to get a good photo, but that's all. It's certainly not worth causing undue stress to an animal for. It will be obvious if a marine creature is uncomfortable with your presence. If they wish to be left alone, they will take evasive action, just like we would. If a fish looks stressed or uncomfortable with your presence, don't harass them - leave them alone. After all, you would appreciate the same level of respect.
If you are photographing something, no matter how engrossed you are, take a look up regularly and check what's going on around you. If you have found something interesting, chances are there is somebody else waiting to have a look as well. Diving is about enjoyment and it is much more enjoyable if everyone is in it together. No-one will be impressed with your photo if you didn't allow them any time to look admire your choice of subject.
If you take risks, you not only endanger yourself, but also those you dive with. No photo is worth compromising on safety for. Dive conservatively, well within you recreational diving limits, keep a good profile, don't allow yourself to get low on air and look after your buddy. Or leave your camera at home. It's an easy choice and one that your fellow divers will also appreciate.
In a nutshell, be considerate, conservative and patient and you will get the most rewards from your hobby. After all, photography is meant to be fun. Let's keep it that way.