If you're alone then I suggest the best places that you should go will be; the Victoria Peak; Symphony of Light; the Cable Car ride in Tung Chung. Disneyland and Ocean park is not ideal without the kids. Don't go to Lan Kwai Fong - you maybe tempted!
Here's a complete guide about the attractions in Hong Kong and the most efficient way on how to get there...
http://www.travel-hongkong-attractions.com