♥ , ☼ , ✓
♥ - What does ‘love’ mean to them?
Terezi doesn't really take the concept of 'Love' all that seriously and doesn't really think about it much. She's never actually been in love and doesn't really desire such a thing. She doesn't hate the concept or anything she just doesn't really care, it's pretty low on her priority list.
☼ - Something that/Someone who makes them happy.
A lot of things make her happy. Like seriously making her happy is the most simple thing ever. Going along with her nonsense makes her happy, the color red makes her happy, learning makes her happy, playing around makes her happy. She's just generally pretty happy.
✓ - How do they react to praise?
depends on the praise and who's giving it
her reactions can range from 4H4H4 OF COURS3 1 WOULDNT SCR3W TH4T UP to TH4NK YOU!! to WOW YOU 4R3 STUP1D depending on who's giving the praise and how much she thinks she deserves it/what its for.