I am a picky eater, have been a picky eater all my life. I managed during my late teenage years and early twenties to acquire a taste for vegetables (and I am grateful that I did), but fruits (apple, grape, etc) are still a problem for me.
I have identified however, that I like
Mango
oranges
lemons
Now I wonder what fruit I could "try" next. Preferably I would not start with Apples and Bananas (as a kid it was constantly suggested I should eat apple/bananas that I don't have the best memories in this regard, I think these will be tougher fruits to start with).
Why am I asking this? Ultimately I want to balance out my diet more and potentially get into a position where I can opt for fruit over chocolate if I want to have something sweet.
A lot of fruits are closely related, like, oranges are actually a hybrid of mandarins and pomelos, so maybe explore a few fruits from different types. If you like nectarines maybe you'll like peaches and apricots. Raspberries/blackberries etc.
Not sure where you live but there are some great tropical fruits, pineapples, passion fruit, lychees, mangosteen, star fruit. I'm biased towards lychee cause we have like 20 trees and they're tasty.
I'd just find a good grocery store produce section and check out different fruits, go by smell, maybe ask if they'll let you sample some. Sounds weird but I worked in a Safeway produce section for a while and the managers encouraged us to cut samples for people.