I think this is the same for every development/ area.
You cannot guarantee any level of rental income and the size of a development has a big impact on your success. If there are another 100 owners trying to rent theirs then it becomes more difficult.
Saying that, the owners that have the most success are those that really put some effort into it, such as advertising on various rental websites, advertising to friends/family/workmates, building their own website, etc.
There’s lots of things you can do but as with any business the returns are proportional to the effort appiled to it.