What I can recommend from personal experience: get Nitrox certified. I had 17 dives on my last liveaboard trip and was completely worn out.Cobra8472:I don't think i'll be too bummed out if we miss out on some of the dives, me and my father were already tired when we had done 2 dives during the day. I'll check into it though.
I did 26 dives on Nitrox 2 weeks ago without any problems.

Laurens