as someone who has only 30 dives and did some simple photography and video in the last 6 of those, i can totally recommend one thing i did on my stay in bali:
hop into the water as often as possible for some snorkelling with your equipment. you will get used to its handling, ups and downs and might even get some shots. it also helped me experiment with perspective, settings and specimen spotting, without a) having to pay for a dive, b) having to think about pressure, deco, buddy..
i was snorkelling and diving down for about 3 hours a day, getting the routine with my equipment from changing/charging batteries, leak testing and changing camera settings. i continued to do this even when i started the scuba, it simply was too fascinating!