Well folks, some of you may remember me from the "newbie chasing dream" thread. I just got back from Key Largo, with many firsts accomplished. First time u/w shooting, first time editing, first time posting to the net. Take a look, pointers welcome. I know I got lazy on a couple of the transitions.
HOW THE HECK DO YOU GUYS KEEP YOUR CAMERAS SO STILL??? I did a search here for "shaky video" (the underlying theme of my short video, lol) and just found a few threads, one about Apple's "shake" program. Is there one for us PC users? In reality, I'd just like to become a better videographer in the first place, so let loose your iron-hand secrets!

The Spiegel Grove has a piece of my old Nikonos somewhere (actually my viewfinder got knocked out heading out and down) so some sections are kind of rocky to being with. The Spiegel is probably a tough one to start out on, we were told if you let go of the granny line before you get down, the next stop is Cuba
Since you are editing on a PC and asking about Apple product I guess you are not the Brian Conner who writes some books on Apple software 
Apple Shake is a program that does many things, including having a smooth cam function which helps with camera shake (Final Cut does also) and they are good to work with, but there are limits of what can be done depending on the footage. In other words some the camera motion in your video cannot be corrected by the software. As to keeping the camera still, larger rigs will help. I shoot a small rig myself and it does take some getting used to, watching your breathing, figuring out which way surge is going, holding the handles with the right pressure. Also some movement is not bad, after all you are underwater and judicious use (and editing into and out of some movement in the video) is not bad. Once you get a few more dives with the rig under your belt it starts coming together.
Probably a good place to start are easier sites. Also the Spiegel is deep (saw you were at 98') so lights would really help. (Not sure if you White Balanced things or not, and at that depth it does not get you far, but a red filter and some balancing would help a bit, more so in shallower waters. )
The next thing to keep in mind is shorter is better in terms of the length of shots and some things need to be left out. One way is that after the first edit, step away and look again and think about the shots and whether someone not on the dive would like it. I usually do a couple of edits of things. One for myself/others on the dive who would find it fun no matter what, a slightly shorter cut with scenes perhaps a bit longer for those who may like the subject, such as Cenotes or the wrecks and then a real one that is paced quicker. Not fast, but more so with the constant asking of whether the shot it too long. Also be careful of the non standard transitions, such as swinging doors and the rest. They can be useful but be careful. Try to get 5-10 seconds of a shot without jumping around to another shot, for instance on the deck moving one way and not jumping to look at something else. Keep an eye on the counter in the viewfinder, 5 seconds takes a long time at 98' Can't tell you how many shots I took where I thought I held it long enough until I got back to my computer 
When you edit usually 5 seconds or so is going to be what you want, but it is good to have a few seconds on either side. Of course there are exceptions, but it is a good general rule. Also there is nothing wrong with getting longer shots, and if you can, do so. It is alot easier to cut things out than not having the footage (but see the planning note below) A far, mid-range and close shot of the subject if possible. Or a continuos shot all the way through.
Of course in an ideal world you could plan everything out, know what shots you are looking for and just get those shots as you sit there waiting. I usually do not have that luxary myself since I do not dive often enough or do repeat dives in one place to be able to just shoot with one firm plan.
I love the Spiegel (only dove it when it was on the side) so thanks for letting me see what it looks like now 