For me, it based on what type of purpose you are buying the property for.

Be extra careful in handling these renovations as some property owners have overspend on the renovation and ended up in liquidity problems. At the end of the day, went they try to sell, sometimes its difficult than the original structure especially when the extension is not preferred by the new prospect.

If cash limited, would suggest take each petty step and not to rush for it.

Assess the property for defects and identify areas which will affect the long term integrity and cause major problems. The 'big four' to look out for are

1) Water damage
2) Plumbing/sewerage
3) Electrical/wiring
4) Presence of termites/major pests like rats

These are usually issues that can cost you up to hundreds of thousands if not nipped in the bud early.

Get a reliable home inspection company to check the property for you and then approach a contractor for costs for fixing/preventing these defects.

Things like painting, appliances, cabinets/wardrobe etc. can be done piece by piece/in stages as and when you get funding.

General recommendation is to not spend more than 10% of the property price on renovation, unless you're rich and this is going to be your forever home/holding it for at least twenty years.

do you have much cash flow in hand? what type of property and for investment or own stay?
it is better for you to get quotation from few contractor before decide what to do...
if you are tight in budget and not in hurry just do it phase by phase, remember to allocate more budget and calculate how much cash flow after deduct your loan etc