I’m sure you will have to add better soil to your garden, but I would speak to someone at a local nursery to find out what and how much you will need and how to apply it to your current soil.

Sandy soils are tricky for sure. As others have mentioned, adding organic matter is the way to go. I live near the beach and it’s an issue for the garden. I use my lawn clippings in the veggie patch first and then the other plants get some when there’s enough to share around. It’s great when you feel like your actually turning over a dirt type substance once you get enough organic matter in there. If you can get hold of the local lawn mowing service you may be able to get a load of clippings for free as they sometimes have to pay to dump it.
Leaf mulch is excellent, especially if you have access to plenty of leaves as it breaks down quite fast. Digging channels in your garden and filling them with leaves works. You will need to top them up with soil as they break down and sink. Digging a new channel next to it and using the excess soil works, It is a slow process but gardens are a labour of love for those that love them. It took me about 8 months before I really started to see tangible results. I didn’t buy any soil though. I only use what I have access to and it’s a really big garden!
Raised beds are awesome for veggies I agree. I hope you are winning your battle.
Good luck

I once had a garden like that. I simply started adding potting soil by every plant I planted and watered them faithfully. Nothing else because I had little money, no chickens or any different to add, although I did add my coffee grounds and tea to the soil (To use coffee grounds as a fertilizer sprinkle them thinly onto your soil, or add them to your compost heap. Despite their color, for the purposes of composting they’re a ‘green’, or nitrogen-rich organic material).
Once the plants started growing the root system of the plant improved the soil and in no time the soil was healthy

I added a few cheap bags of potting mix to the vege patch, and some good chook poo, then after a couple of weeks, planted seedlings – keep the water up and add seasol and if you notice leaves going a little yellow, they need a mineral like Epsom salts watered onto them

Hi, I don’t know how you’re going with your garden since you posted this question; I hope its going well. As others have said, adding organic matter or making raised beds is great. Depending on where in Australia you live in, if you are close to a sugar mill, you can purchase filter press (also called mill mud) and dig through. Carrots love sandy soil and I’ve actually brought some in for a raised bed because my soil is not loose enough (but carrots won’t grow straight in filter press). Your local nursery should be able to put you on to a good fertiliser for your soil type. I use a cheaper equivalent to Seasol. For anything fast growing for kids, radishes, chives, and bok choi are a good start and tolerate a wide range of soil types. As far as fruit trees, I can’t comment as our red dirt is far from sandy soil. I can only suggest talking to your local nursery about what thrives in your area, or look at what others are successfully growing nearby. Otherwise, its a matter of mulching well, watering when required, enjoying the sunshine and trial and error. Good luck.

we grow quite successfully on the Mornington Peninsula – we added some potting mix, chook poo and regularly seasol the crops – oh and if you have yellow leaves, add some Epsom salts to the base of the plants

Probably easiest to use pots or raised garden beds as others have suggested.

Sandy soil is hard to work with. You’ll need to add lots of organic matter to pump nutrients through it and it drains way too quick. Like the other, I’d suggest pots or raised garden beds.

Lots of things can be grown in big tubs with potting mix. You can get inexpensive ones from Bunnings. Last year I bought 4 big black tubs (about $7 each) and grew lettuces, herbs, chives, chillies, kale and spinach in them. Otherwise, you will need to build up your soil with lots of organic matter and compost.

I have the opposite problem I have clay soil

You could possibly try making a raided garden bed (or beds) there are plenty of varieties available, its intensive too so the yields are quite high for the space used!