for an internship, I'm going to move to Singapore in September - I'd like to stay at a place where it's easy to meet other young people (students, interns), a shared flat would be great. Given that it's always risky having to rent room not being able to see thr place before, is there something I should be cautious about (e.g. rip-offs, deposits)? How much time should I plan to spend looking for a place?
Since it's not allowed to rent out residential property (even sublet rooms) for less than 6 months, you may have to stay in a hotel, hostel or Serviced Apartment.
Look for a room in a student hostel - they are the cheapest option you have (at S$1000-1500/month) and fulfil your other requirements.