You can try to find and rent a property on your own, but you will need to be prepared for the stress that comes with it like in most big cities around the world. Also many landlords do not want to deal directly with tenants, especially newcomers and foreigners, or they don not have any desire to negotiate rents or other demands of renting with the future tenant. That is why you will find it easier to go by agencies even though you will have to pay fees for the agency.
Also you can imagine that the situation changes with lower budget accommodation like studio flats and flat shares, serviced apartments and short lease accommodation. On the other hand some owners do not want to pay agency commissions so are more inclined to deal with future tenants in person. In this case, be ready to negotiate and sign the lease by yourself (unless you can find help), which might be rather complicated if you do not speak chinese at all.
Here is a useful website for more information:
As usual, when you deal with agencies; you do not want to waste your time and you have to set few boundaries like what the number of bedrooms you are seeking for, what is the maximum rent monthly you are ready to pay...
Be aware of another fact is that some flats in Hong Kong can be pretty small and some agencies might ask YOUR height as some beds are not long enough!
Here is a non-exhaustive list of online property web sites that you may want to contact for housing:
And here are some Real Estates agencies that would be interesting to check out: