If you really wanna enjoy Goa in 3 days then you need to decide beforehand what exactly to want. South and North Goa are completely different. I am too traveling to Goa from 26th to 28th of Oct. A solo trip. This will be my second trip to Goa. I will be staying in Hostels with Hippies.
North goa has everything at one place. Clubbing- Lpk , Tito’s , Mambos, sinq, Bombay adda(only on weekends worth going to)
Places to eat and chill- thalassa, curlies , cafe lilliput, cafe mojo , Soro. Stay- search on make my trip based on your budget and hotels reviews. Beaches- Anjuna , Vagator , Baga , Calangute.
Since i stayed in north goa so will tell you accordingly.
day 1 - roam around explore beaches forts etc.
day 2- Dudhsagar waterfalls & a quick visit to old goa if u wish to.
day 3- clubbing and all.