How do you repair a compacted lawn?

[#1]

If your lawn is compacted, I suggest using a lawn aerator. Options include spiked rollers, pronged aerators and even sandals with spikes. 

If you also need to level the lawn, I recommend using Scotts Lawn Builder 25L Organic Lawn Soil Topdress & Underlay. If you already have native soil in your garden that you can utilise, you can use it but I would suggest adding Munns Professional 10kg Instant Turf And Seed Starter Fertiliser. 

Applying topdressing to an existing lawn is best done in autumn, after the peak of summer has passed and before the beginning of winter rains. It's best to avoid topdressing in mid-summer.

Then to repair any bare patches, you can either put new lawn seed in the area or dig out the spot and install a roll of turf into it. The best time to seed new lawns and patch existing turf is in mid-spring, allowing time for the seeds to germinate and the grass to establish before summer.

The guide How to repair a lawn by experienced Bunnings Workshop member Adam also has helpful advice. - EricL