I have to agree with ballast. You need to think every manuever through. If you're not accustomed to operating a vessel of that size, or even a twin screw vessel there will be a lot to get used to. If you currently operate twin screw vessels without the independent gear and throttle controls then you have the hurdle of habit to overcome.
Make cautious approaches, I started by using throttle as little as possible. If your approach is slow and properly planned, in fair weather conditions, you should be able to get away with using mostly gear selections.
Always make smooth slow movements of the controls, that way, if and when you select the throttle for the gear or vice versa, you can catch the error before it's an accident. After the first couple of approaches, it will be like second nature. Also sit in the seat and go through the motions without the engines on. That helped me as well.