Noida flat owners – what's one thing you wish you knew?

Just moved into Shiv Shakti Homes in Sector 26 last month. Possession was in March, but things nobody told me: the advertised rental yield is a joke! Honestly not sure how anyone gets close to those numbers. Am I the only one finding it tough to find tenants at the expected rent? Has anyone else faced this? Also, is it worth holding property for 10+ years for maximum gain, or selling earlier?