Reservations are usually recommended on Friday and Saturday nights (which won’t worry you) but also if there are any really popular places you want to specifically eat at. There are a few popular restaurants that only take reservations if you have a certain number of guests (usually 6+) and for everyone else it’s first come first served.
Without knowing your budget and exactly where in Melbourne you’ll be staying, here are a few of my favourites in the CBD you could google to see if you like the look of (some cheap eats and some expensive)- Maha, Chin Chin, Tipo 00, Rice Paper Scissors, Hutong Dumplings, Ezard, Sezar, Supernormal, Rockpool, MoVida.
If you’re after something different there is also the Tramcar restaurant (you will definitely need to book ahead for this).
Also keep in mind that a lot of restaurants are closed on Monday nights so it might be worth researching what is open on Mondays rather than showing up to places disappointed.
Enjoy Melbourne!