You can do breath hold tables such as in the following link/website. There is some good articles and info on equilising in there too once you browse around the site. It's good to get a proper handle on equalising.
Do a freediving course, you can book through Apnea Australia or there are others around that run courses in Melbourne from time to time, Walter Steyn is one of them I believe. I think a few of the guys from this forum have done the courses and highly recommend them.
Training in a local pool helps, I used to train with a group at the Melbourne Aquatic Centre last year before my time table changed for looking after my daughter and I could no longer attend. I got a lot out of the training sessions while I was attending.
Keep diving, the more often you dive the better you get. Don't push it too hard though, take small steps and have someone with you.
With the lack of diving lately my breath hold has gone to rubbish compared to last summer, I need to get out more...
http://www.apneaaustralia.com.au/resources/articles/breath-hold-training-tables