I think the letter C is the most difficult consonant to master when learning Italian. I've seen over the 18 years that I've been teaching Italian, that my students continually struggle with its sound. When the C is followed by an 'e' or an 'i' it has a sound like the 'ch' in church. So words like 'ciao', 'cena', 'ciliegia', 'amatriciana', and 'celebrazione' all contain this 'ch' sound. When the C is followed by an 'a', 'o', 'u' or 'h', the sound is like the K in the word 'key'. Have you ever been in a restaurant and wanted to order that delicious appetizer that usually consists of grilled bread with a tomato topping? It's written as 'bruschetta' and therefore pronounced like 'broo-ske-tah'. I've had to correct my waiter/waitress on a couple different occasions in order to advise them on the correct sound that the 'ch' makes. One woman actually argued with me and said that I was wrong.. But if you want to do it right, remember this simple rule about which vowel follows the C-and also the H! Check out my YouTube video on pronunciation if you're still wanting practice. Buono studio!