First of all congratulations and welcome to the underwater world. You’re so lucky to be going to Australia. Definitely on my to do list.
First of all, your list of new diver mistakes to avoid....
1. Don’t forget to unstrap your tank from the rack before putting it on and trying to stand up. But if you do, just know that I know divers with hundreds of dives that still do this from time to time.
2. Both before you jump into the water and before you descend, Regulator in...snorkel out. I’ve done it myself.
3. Take appropriate sea sickness medication if you are prone to motion sickness. The boat won’t go back if you get sick and there is nothing worse.
4. Don’t be afraid to ask questions or for help. VERY IMPORTANT! There is no such thing as a stupid question.
5. Make sure you are weighted properly. This is tough to do with a full tank, but it never fails that as your tank starts to run low on air, a couple pounds underweight will cause an ascent to the surface you can’t stop. If it happens, remember to keep breathing. And then consult the DM on the boat and get more weight for the next dive.
6. If you are wearing a hood, make sure your mask seals your face under the lip of the hood. But if you are in tropical water you probably won’t have a hood to deal with.
That’s all I can think of first off. I’m sure more buddies from this site will chime in. They are very helpful here.
Second I’d like to address your divebuddy anxiety. Relax! You’re on vacation. If you’re a single on a boat just let the Divemaster on the boat know you are looking for a buddy and that you are fairly new. The DM will no doubt ask the group any how. Either an experienced diver will come forward, or the DM will offer to take you down himself. When you get paired up with a buddy it’s a good idea to suggest a buddy equipment check. You should both know how to drop each other’s weights if needed, as well as what type of Alternate Air source he/she has and where to find it. This knowledge will increase both of your confidence and comfort level diving together. Also make sure to mention anything about your abilities or comfort level; perhaps you tend to descend slowly to help your equalization, or you prefer your buddy to lead, or you are not comfortable going beyond a certain depth, or you plan to do a 3 minute safety stop and your hand signal for it, or your desired air pressure to turn around and head back, plus the minimum air pressure you both plan to ascend with. The more you discuss the more you both will be comfortable. Discuss your dive plan!
You will be amazed how many new friends you will make on the boat being a single diver. Have fun and enjoy the adventure. And if you ever end up on a cold water trip to Southern California for diving I’d be happy to buddy with you any time.
Rich