I have to agree with Max. Spend the first couple of days adjusting and chilling out then venture a little further away. Try the night markets always good fun. Take a taxi and try a couple of nights in a beach hut like mandrem only an hour away from candolim but very nice.
There are lots of companies that do trips to the waterfalls and things like that. if you find a taxi driver you like then compare the prices and haggle. Dont be afraid to try something new if its food or an experiance.
Keep your common sense dont do things there that you wouldnt do at home like keep an eye on your bag dont flash too much cash and keep safe.
Most of all enjoy it the people the food and hopefully the only thing you will get bitten by is the goa bug which makes you love it and hurry back
