I sold my place in Northcote last year.

1. Do your homework re agents. Research through realestate.com.au (or similar) what houses are for sale in your local area and then through reiv.com.au what sold and for what price. You'll get a feel for their approach. Many agents underquote and properties get passed in because people aren't prepared to go that high (particularly in today's market). Others seem to sell before auction for slightly less than I think things would go for (probably not wanting to risk an auction and losing out on a commission). Ideally you want to find a balance - an agent that sells property for a realistic/good price.

2. Do your homework re what's for sale. You will soon learn from other houses, how to present yours. Just look at the photos.

3. What we did to our place:

Repainted. We had neutral colours anyway but they needed freshening up. Both inside and outside.
Fix anything that needs fixing.
Declutter (we removed about 30 boxes of stuff and it was a pretty small house, you need to be ruthless), remove any extraneous furniture and decoration. Remove anything overly quirky from the house/garden.
We had our front and back gardens tidied up - new plants, new mulch.
You really do need to make it look like a showhome. That's what people expect.
Veggie garden I would keep if it's blooming.
Dog run - dunno, if it makes the garden look smaller that may work against you. Hard to say without seeing.

Our agent organised everything from painting to gardening to styling. We had some pieces of furniture brought in. A lot of agents offer this service these days in Melbourne.