I also own properties that doesn't do well. Based on my experience dealing with properties I can share some lessons learnt and best practise:

1. Buy only at good location, even though they are very expensive. LOCATION, LOCATION, LOCATION mantra is never wrong. Even during COVID time, after I collect my key the very next day I advertise it in Mudah (not a popular portal) - I still get 3 random calls from property agents in a day!

2. If you can get reliable cleaner go for short term let like Airbnb rather than yearly rent. Much higher yield because you charge daily rate

3. Target expatriates. I raised the rate so high that it filter out local peasants (sorry). Those that inquire and book generally the tenant profile are good. They are cleaner and can take care of your property very well. Some even check-in with their OWN MAID. Knowing that it gave me assurance that the unit will be well kept