Looking for ideas to retain water and help my garden 🪴

G’day! I’m new to learning about permaculture and I’d love to implement some ideas into my garden. I live along the coast in the NW of Western Australia in a semi-arid zone. The house I’m in is a rental. Up until I recently moved in, the garden hasn’t been watered or given much attention. So far I’ve pruned the fruit trees, fed and mulched them all. I water them daily by hand. They’re all fruiting, except the mango, but it’s showing buds of promise. I’ve drawn a diagram of the area for reference. So far this year it’s rained about 9 days in total. We’re coming into cyclone season and can expect rain towards the end of the year 🌧️ Is there anything more I can be doing to help and potentially prepare for the upcoming rain?