IMO a few stories on property investors and their journey, if you can find any stories, as they are usually interesting.
Also, expanding on the previous post under Sales - the type of sale and the reasons behind each type, auction, private treaty, silent etc. Also touching on the advertising behind the sales and what is used when and why, i.e., internet, signboards, newspaper local and city-wide, leaflet-direct advertising etc.
Not sure if you wanted any humour in the blog, however if you did, some topics I would go with: Real Estate agents and the cars they drive; real estate agents and the phones they use, and just make up something funny linking each brand to the personality of the agent.