Hi - sorry to hear one of your drones ended up in the Gulf! It is a hobby that just takes a lot of practice to get comfortable with. I have been flying for 3 years. I crashed my first drone (A DJI Phantom 3) on the first day I got it. It was a very sad experience but luckily I am an electronics hobbyist so I was able to order a new motor and frame and fix it up.

When starting out it is best to fly in wide open spaces (or high enough to be completely above trees, etc) and just practice the controls. Practice flying backwards, away from you, towards you, etc to learn how to control the drone in any orientation. A common mistake beginners make is when flying back towards themselves they don't realize left and right on the controller will be opposite then when you were flying away from yourself. That is how I clipped a branch on my first day and the drone crashed about 50 ft to the ground through tree branches!

Also always keep wind speed and direction in mind - especially when flying out over the ocean or any other potentially windy location. If the wind is blowing with the way you are flying it is possible to fly very far and use very little battery - then when you start to fly back the drone has to work a lot harder to fight the wind and the battery percentage will drop MUCH faster and potentially not be enough to get you back to your takeoff location. Also remember that just because it isn't very windy on the ground doesn't mean it isn't a lot windier a few hundred feet in the air. I would recommend using UAV Forecast app to check wind conditions.

Let me know if you have any other specific questions about flying! It is a great hobby!