I am afraid that's a question that no one can answer (even those who think they did). There are no specific coins to trade. You do your own search, and you choose what coin to trade. That's how you will get experience. And don't take anyone's advice – they will troll you for their own benefits (or amusement).
Exactly, in trading industry you must be very careful to choose what coin to trade. Otherwise, you will lose your money. You need to be wise. From now and then, there is always trusted coins that are tested by the professionals. You have to check first their longness in industry especially the value of the coins you prefer.