2. Know which station to get down at:
Goa has two main stations, Madgaon and Thivim. If one is travelling to South Goa, then choose to get down at Madgaon Station. If one is planning to stay in North Goa, prefer Thivim. If your train doesn't directly go to Thivim, get a connecting train from Madgaon station. Taking a cab or an auto from Madgaon to North Goa will cost atleast 1200 Rupees.
3. Travelling inside Goa:
There are NO Ola and Uber cabs in the state and hence one has to either rely on autos or private cabs. The best way though is to rent two wheelers or cars which are very easily available throughout the city. One can get Activa for 200 Rupees a day, bikes and cars are available at an affordable rate too.
This depends on the type of accommodation the group is fine with. There are many hostels available in the city that afford cheap and safe accommodation for the group (Zostel-Goa) . One can find cheap and good accommodation through Airbnb throughout Goa. For unmarried couples, one can look through Oyo Rooms which allow couples. There are a lot many beach huts as well where one can bargain and get a good deal. Larger the group, cheaper the accommodation gets.
5. Places to roam around:
This totally depends on one's interest. Goa is full of beaches, be it North or South, you will never find yourself missing out on the wonderful beaches that Goa has to offer. One can just laze around at the beach, a lot of beach shacks have their sunbeds where you can just lie down for hours together and enjoy the view. Sunset is one sight that must not be missed here.
Apart from the beaches, Goa has the Dudhsagar waterfalls that is located on the Goa Karnataka border.