If your contract was written correctly, then there should have been either no land tax adjustment required at settlement or a minimal adjustment. The Office of State Revenue is pretty good at updating the database these days and accordingly post settlement land tax problems are now much reduced. If you get a land tax bill, check the contract and if you are liable pay, then do so as soon as possible.
In advance of settlement you need to get together all of the keys, codes, warranty certificates, product manuals and other paperwork that your buyers are entitled to receive once settlement has taken place. You will have contractual obligations to deliver this material, usually on settlement. Sometimes that is handled by your representative (for example the Agent) handing over a package of material onsite. Make sure everything is clearly labelled (for example keys) to avoid annoying your buyers.