Looking for 1st Home in Sydney

I'd suggest a unit either in Northern Beaches – Manly/Fairlight/Harboard or a unit in Concord close to canada bay and as far away from strathfield as you can.
For $300k you can still buy a clad 3 bed room house in Merrylands. Even though the area is a not the best, it ticks a lot of boxs in terms of what/where to look.
You should be able to find a unit for $400k in the upper north shore area like Chatswood/Northbridge/Cammeray .
Look for all the normal things ,transport,cafe's bla bla bla.
I'd be inclined to look at the suburbs that haven't done so well in recent years as opposed to those that have shown 10% growth for the last few years running.

Personally i would be looking on the inner west train line (heavy rail close to the city will be more and more sort after as the city grows and its harder to commute by car) becuase thats as close as you can get to the city an be close to transport on a budget and in an area that is going through a demographic shift which inturn is improving the lifestyle faclities (and property value). Of course it all depends on what type of area you choose to live and what your lifestyle priorities are. If you looking/considering the hornsby area (as suggested by someone) than you probably woudnt want to live in say Petersham in the Inner west anymore than someone in Mosman would choose Newtown. However as an investor i definitely wouldnt buy in hornsby, but I would invest in the inner west particularly on the train line, between 5 and 15minutes to central, too easy.

Anyhow you really need to decide on your budget and what you want out of it before you can get some sound advise from us in terms of property type.However if you went with a unit my advise woud be to go for scarcity value to max capital growth and to have a solid investment. Like an Art deco unit for example, make sure its a small block (no more than 12 apartments preffer 6 or 4 as ideal)) , these will always be sort after and in demand, character homes are always going to hold value better than poorly designed new apartment developments which are usually overpriced (and about to start depreciiating rapidly and supply is always fluctuating).. Buy an older style on the trainline do a minor reno and hold on and youll be in a good place in the future.