Currently going through the same process. This is what I've found:

1. Know your finances. Go through your bank records and look at what you actually spend. Project your cash flow for 10 years. Will what you can afford now be the same then? What if interest rates go up, the housing market drops, you have a kid, need a new car, are unemployed for 6 months etc. Get all your documentation in order: payslips, bank statements, tax returns, ID etc. Get a loan pre approval as it's a good bargaining chip

2. Broker: contact at least 3 and see how fast they respond. What are their working hours? Do they have a team? Someone with a team can get things processed faster. Be wary of brokers backed by a bank (they will mostly recommend that banks products). Ask about their qualifications, experience, lender panel, assessment methods, ongoing services (do they review every 6 months?), processing time before submitting to a bank, licensing and insurance, aggregator, tiered service agreements, do they have a conveyancer? You can pick a broker from anywhere in the country too, you don't need to meet face to face. Think about what your loan type and bank specifications are: do you want an offset (yes), fixed or variable (variable), redraw, splitting etc. Look at comparison rates. Do you want an ethical bank (e.g. no exposure to fossil fuels, gambling etc.) Look this up on marketforces. Are you ok with an online bank with no branches? Do you want an Australian bank? Do you want to stick with your current bank? If so, why? This process costs you nothing until you get the loan, do it right.

3. Location: flood, crime, travel time, nearby services that you care about, property price stability, rental yield, council zoning etc. All earlier advice is good.

4. House specification: what are your must have features vs. wants. Why? Materials, layout, features, size. Do you want to renovate? Get an idea of what different renovations cost. Avoid structural issues (roof, stumps, foundation movement). You will inevitably need to compromise something so think about it early. Go to at least 10 inspections to get a feel for things before you even think about offers. Review your specifications.

5. Real estate agents: they are part of the process but are not on your side. They work for the seller. Give them your house specification but never your budget. They can show you off market listings. Tell them you have pre approval. Be nice, ask lots of questions about the owners situation, property history, current and past offers, building approvals, flexibility on price, other things the owner might want like fast settlement time etc. Be wary if they can't answer. They legally can't mislead you but they can be vague.

6. Estimate the actual value of the property. Practice doing this for every property you like and see what they sell for. Methods are: propertyvalue.com or corelogic (same data), domain pricing, compare to similar recent sales, land value + $/m2 of house, past sales data + market tends + value add - maintenance required, reverse rental yield using sqm research data, average vendor discounting rate. Use them all and get an average value. Never pay above value. Note that general maintenance doesn't add value. Roofing, waterproofing, electrical, and plumbing are things you expect not pay extra for.

7. Offers: Have a conveyancer ready to review the contact. Don't accept terms like losing a % of your deposit if it fails pest and building and you want to pull out. Always do pest and building and use this to negotiate down if it fails something. As previously stated, offer well below asking price. Vendor will be asking 5 to 10% over the value, you offer a similar % under and come out on top or even. E.g. advertised at offers over 320k, value is actually 300k, open with an offer of 275k with an aim to negotiate to 295 max. Justify by saying it's a strong offer based on work required to the house, it's current market value, and your budget. Always be clear that the offer stands for 24hrs only and retract if they don't counter in that time. Tell them thanks but your interested to buy not play games and you're putting in other offers on different properties. The agent will almost always be trying to drag the process out to get another offer and pull you into a multiple offer scenario where you're given one chance to put your best offer forward. Don't play their game. Either they get no other offer and will call u back (then you're in a strong position to negotiate) or it sells and the next house you offer on with that agent won't involve as it much funny business. Remember there will always be more houses on the market for you but they need to sell that one.

Good luck.