Christy:
You live in a great location for photography, so I'm sure you'll have lots of opportunities to improve. I would suggest you get a little closer to those people taking the wedding and fashion shots. Don't interrupt the shoot, but get to where you can see how they're working the light and the background. You will definitely learn a thing or two just by watching.
Now, for your shot, I'm afraid it was doomed from the start. The scene greatly exceeded the dynamic range of your sensor. There was just too much difference between the brightest and darkest spots in the scene, so you have the sun completely overexposed on the left, and the shoreline and people underexposed. Unless you took several exposures at different settings and combined them with an HDR (High Dynamic Range) program, there's just no saving this. HDR is very difficult (at least for me) with moving subjects, so it probably wouldn't have worked here.
Your best bet would have been to move to an angle that excluded the sun and the brightest parts of the sky. Then you could have gotten a better exposure on the people. Alternately, you could have waited until the sun was just below the horizon, then took some shots. You really need a tripod and remote release to make these types of shots work well.
Keep trying. I'm sure tomorrow's sunset will be just as beautiful, so get out there and shoot it again.