March - April is a wonderful time to visit Sri Lanka. However, please pre-book hotels especially for April, as for about 2 weeks of the month there is the Sinhala and Tamil New Year, where most of Sri Lanka is on vacation.
Are you vegetarian? Then you need to aware of the food items. Many of them, even if vegetarian have something called 'maldive fish' in them, which pure vegetarians or vegans will not eat.
Food is really spicy here, so please ask for less-spicy food. For Indians, I would liken the 'hotness' to the Chettinad cuisine level.http://www.tayafinchonline.com/