The following preferences might be subjective, feel free to adapt according to your liking:

• Types: Arabica.
• Grown altitude: The higher, the better.
• Acidity: The more acidic, the better.
• Color: The lighter, the better.
• Flavor profile: Fruity, especially berry-like, won’t go wrong.
• Bean hardness: The harder, the better. (Please don’t say that’s what she said)
• Roast date: The fresher the better. (Some might say 2-4 weeks is the prime, meh)

Not a connoisseur; learned these from my brother.