@melbourne_wanderer@aussie.zone I wrote out a long reply to your question about tomatoes yesterday and my app crashed before I posted it and I lost it all. I will try again today.

Good soil is the most important starting point - it should have good drainage and lots of organic matter. Digging in lots of compost fixes most faults (I like the cheap "cow manure blend" that bunnings sells - not a high level of nutrients so you can use lots to build up soil structure).

Don't use high nitrogen fertilizer (there is usually an N:P:K number on the packet, look for ones where the first (N) number is lowest relative to the others. Nigrogen encourages lot of leaves and will give you a great looking plant, but not much fruit.

Tomato plants can grow new roots from the stems, so plant them deeply, burying the stem and leaving just the leaves out.

Use lots of mulch (5-10cm deep) to keep the soil moist over summer. In the hottest weather your plants will also benefit from some shade - just some shade cloth draped over some garden stakes should be fine, you don't need to build a greenhouse.

The plants will need support to stop them flopping all over the ground. You could spend a small fortune on fancy tomato cages, but my preferred method is the Florida weave. Simple and very effective.

Disregard anything you see about pruning - you don't need the extra complexity right now, and there is no expert agreement about whether it is beneficial or not (but many strong opinions on both sides).